Introduction

Promoting healthy lifestyles in areas such as diet, physical activity, smoking and drinking has become a key priority area in the public and private sector, with the present wellness market reportedly valued at US$4.5T (McGroarty, 2018). Relevant to this industry is the science of ‘health behaviour change’ devoted to exploring and expanding the understanding of theories, determinants and interventions in this area (e.g., Davidson and Scholz, 2020). Promoting healthier lifestyles is important as unhealthy behaviours increase the probability of manifest disorders such as obesity, diabetes, depression, cancer and cardiovascular disease, as well as untold personal and familial suffering and significant economic burden (World Cancer Research Fund/American Institute for Cancer Research, 2018). Healthy lifestyles and mental health are closely related (e.g., Nagasu et al., 2019) and unhealthy lifestyle choices can cross over into pathology, with substance abuse being a major contributor to premature death (Case and Deaton, 2015). Tobacco and alcohol use in particular constitute a substantial health burden, together accounting for approximately 15% of global deaths (World Health Organization, 2017b, 2018). Both obesity (World Health Organization, 2020) and physical inactivity (Ding et al., 2016) remain highly prevalent worldwide, despite several decades of public health campaigns and policies intended to combat them.

Psychedelic¹ compounds such as LSD (lysergic acid diethylamide), psilocybin (present in ‘magic mushrooms’) and DMT (dimethyltryptamine, present in ayahuasca² and other preparations) may not seem like obvious tools for promoting healthier living. However, plants and fungi with psychedelic potential have been used by humans for centuries, if not millennia, for holistic ‘healing’ of body and mind (Akers et al., 2011; Lowy, 1971; Schultes, 1969). In the mid-20th century, aided by the laboratory synthesis of mescaline, LSD and psilocybin, scientists began to systematically test the effects of these compounds, with hundreds of studies performed. Several of these focused on the ability of psychedelics to promote traditional psychotherapy—with positive results claimed in the treatment of mood disorders and addictions, in particular. For example, a systematic review of 21 studies published between 1949 and 1973 covering the use of LSD and psilocybin for treating depression reported that 79% of participants had clinician-judged improvement after treatment (Rucker et al., 2016). In this period, over 40,000 patients participated in more than 1000 published studies with psychedelics, with many encouraging outcomes (Grinspoon, 1981; Grinspoon and Bakalar, 1979). Circa 1970, psychedelic research was halted due to prohibitive new legislation with formidable barriers to research, inaccessibility of drug product, a shifted public opinion, professional marginalization and lack of funding (Bonson, 2018; Johnson et al., 2008).

The 21st century has witnessed a so-called ‘renaissance’ of human research with psychedelic compounds. This is reflected in mainstream coverage of the topic, advocacy movements (e.g., Mazzei, 2019) and improved funding for clinical research (e.g., Emerson et al., 2014; Nichols, 2014; Sessa, 2018). Research of psychedelic-assisted psychotherapy has been published or is now being planned or underway for a range of psychiatric conditions including cancer-related distress (Gasser et al., 2014, 2015; Griffiths et al., 2016; Grob et al., 2011; Ross et al., 2016), depression (e.g., Carhart-Harris et al., 2021; National Library of Medicine [NLM], 2017a, 2019b), anxiety (NLM, 2017b), substance use disorders (e.g., Bogenschutz et al., 2015; Johnson et al., 2014; Moreno et al., 2006), obsessive compulsive disorder (Moreno et al., 2006) and eating disorders (Carhart-Harris et al., 2021). Despite mostly small-sample studies, published results are largely promising (Johnson and Griffiths, 2017). In the USA, the FDA has granted ‘Breakthrough Therapy Designation’ to psilocybin therapy for depression for two separate sponsors, effectively fast-tracking the development pathway to licensing if clear criteria are met. The substances ketamine and MDMA (3,4-methylenedioxymethamphetamine), which can induce psychedelic-like effects, are also being studied for treating depression, posttraumatic stress disorder and substance abuse (e.g., Krediet et al., 2020). MDMA has also been granted Breakthrough Therapy Designation by the US FDA for treating PTSD. However, because ketamine and MDMA are not considered ‘classic psychedelics’ (their mechanisms of action only partially overlap with those of psilocybin, LSD or DMT), they will not be covered in this review.

How do psychedelics work? A summary of neurobiological findings

Classic psychedelics are direct agonists at the serotonin (5-hydroxytryptamine, or 5-HT) 2A receptor (5-HT2AR) subtype, and while all of the most popular psychedelics also have activity at other receptor subtypes, agonism at the 5-HT2AR appears to be key to their main action (Glennon et al., 1984; Preller et al., 2017; Vollenweider, 1998; Winter et al., 2004). Psychedelics have a favourable toxicity profile and therapeutic index (Van Amsterdam et al., 2015), and apparently negligible addiction potential (Rucker et al., 2018). The main hazards relate to the intensity of the altered state of consciousness they produce, particularly at higher doses, and the need for professional supervision under these conditions (Johnson et al., 2008).

The effect of stimulating the 5-HT2AR is to increase the postsynaptic gain of the host neuron, which is commensurate with it becoming more excitable to input. 5-HT2ARs are most densely expressed on cortical layer V pyramidal neurons, important information integration units (Jakab and Goldman-Rakic, 1998). This increase in postsynaptic gain translates into a spike-wave decoherence at the population level (Celada et al., 2008) and increase in the complexity, unpredictability or entropy of field potentials—an effect that correlates closely with the intensity of subjective effects in humans (Schartner et al., 2017). Higher, macroscopic level effects include the dysregulation of large-scale intrinsic networks (Carhart-Harris et al., 2016), increase in the repertoire of high-spatial frequency global brain states (Atasoy et al., 2018), and an increase in the communication between large-scale intrinsic networks (Carhart-Harris et al., 2016; Tagliazucchi et al., 2016). At the anatomical level, psychedelics have been found to promote cortical synaptogenesis, an important marker of neuroplasticity (Ly et al., 2018). The pertinent question, however, is: how do these effects relate to the putative therapeutic action of psychedelic therapy?

Recently a model was introduced to directly address this question (Carhart-Harris and Friston, 2019). It takes inspiration from the hierarchical predictive processing model of global brain function, which states that the brain strives to model its world in order to minimize surprising exchanges with it and thus, promote its mastery. Applied to psychedelics, the so-called ‘REBUS’ model, ‘relaxed beliefs under psychedelics’ states that psychedelics decrease the prediction-weighting of priors at different levels of the brain’s functional hierarchy—but particularly its highest hierarchical levels. In plainer language, this relates to dysregulated activity in relevant dimensions of brain function thought to encode high-level predictive models, such as the strength of oscillatory rhythms (such as the predominant alpha rhythm) and the integrity of intrinsic brain networks (such as the default-mode network). In more intuitive experiential terms, this effect relates to a felt relaxation of beliefs or assumptions e.g., about one’s self, relationships with others, or to the world more generally. In many psychiatric disorders, it is argued that habits of mind and behaviour, as well as beliefs, become ‘too precise’, meaning they are rigidly encoded and too influential. Examples include the negative cognitive bias in depression, specific cravings in addictions, specific fears in anxiety disorders, specific obsessions in obsessive compulsive disorder and specific bodily beliefs in body image disorders. According to the REBUS model, psychedelics afford the individual respite from weighty beliefs and thus a window of opportunity for change that can be exploited if combined with a commitment to therapeutic development (Carhart-Harris, 2019).

The evidence presented above highlights a potentially relevant link between the neuroscientific findings and behavioural change which may be facilitated by psychedelics. Revision of high-order mechanisms not only have an introspective consequence (i.e., in affective and cognitive domains) but may also result in exploratory behaviour which is consistent with new patterns and beliefs acquired during or after the acute experience. For example, a new appreciation for natural environments (Lyons and Carhart-Harris, 2018) could result in an increase in nature immersion behaviours (e.g., choosing parks or riverside trails to be more physically active) or a more sustainable shopping and dietary pattern. Such an increase in exploration of new behaviours would be consistent with an increase in the personality domain called ‘openness to experience,’ which has been shown to be increased by psilocybin (MacLean et al., 2011). From a mechanistic point of view, evidence from psychology and neuroscience experiments show that psychedelics are able to induce flexible patterns of thinking in different cognitive domains, which occur at a basic level of perception (Kometer et al., 2011; Timmermann et al., 2018), as well as on domains related to language and semantics (Family et al., 2016). Psychedelics may also enhance creative thinking (Kuypers et al., 2016) during acute states, depending on the context in which the experience takes place (Hartogsohn, 2016). It is thus reasonable to assume that the effects of psychedelics at multiple levels of the cognitive hierarchy may result in long-term changes in behaviour.

Could psychedelic experiences increase self-determination?

Self-determination, or perceived autonomy, can be defined as the degree of self-endorsement of one’s actions at the highest order of reflection (Ryan and Deci, 2006). Self-determined motivation is consistently associated with improved psychological well-being and with engagement with—and persistence in—a variety of tasks and long-term behaviours (Ntoumanis et al., 2020). Consequently, the concept has been explored in studies in health behaviour change, in areas such as dental hygiene (Halvari et al., 2019), diet, exercise and obesity (Teixeira et al., 2012a), diabetes (Phillips and Guarnaccia, 2020) and tobacco cessation (Williams et al., 2016), with generally encouraging results (Leblanc et al., 2016; Sheeran et al., 2020; Teixeira et al., 2012b). We propose that it could present a fruitful psychological framework from which to understand how psychedelics could assist in lifestyle change, especially from a motivational viewpoint.

According to self-determination theory (SDT; Ryan and Deci, 2017), at the root of self-determined motivation and behaviour is the satisfaction of the three psychological needs of competence, autonomy and relatedness (see Table 1 from Teixeira et al., 2020). Much the same as the five human needs, as defined by Maslow, may be necessary for human survival and development (Maslow, 1943), SDT posits that competence, autonomy and relatedness are innate essential psychological needs for mental health and for psychological growth. It suggests that human beings are naturally inclined to ‘engage in interesting activities, to exercise capacities, to pursue connectedness in social groups, and to integrate intrapsychic and interpersonal experiences into a relative unity’ (Deci and Ryan, 2000) but this will occur only to the extent basic psychological needs are satisfied. SDT also makes reference to the concept of ‘true’ or ‘core’ self,³ one which researchers and practitioners involved with psychedelic therapy will easily relate to many participants’ personal accounts (e.g., Noorani et al., 2018; Watts et al., 2017).

We hypothesize that competence (akin to a sense of self-efficacy and confidence in one’s capacities), autonomy (i.e., wholehearted self-endorsement of one’s actions) and interpersonal relatedness are all factors which psychedelics could plausibly influence. Although at present we have no direct evidence for such effects, accounts of participants in research trials for depression (Watts et al., 2017), alcohol cessation (Nielson et al., 2018) and smoking cessation (Noorani et al., 2018) suggest this could be the case. Regarding competence, Nielson et al. (2018) included a category of ‘confidence, motivation and resolve’ and another of ‘commitment to change’ as descriptive of participants’ experiences. In turn, Watts et al. (2017) reported feeling more ‘confident’, ‘resilient’ and ‘effective’. In relation to ‘autonomy,’ Noorani et al. (2018) found insights into self-identity (e.g., unveiling of true self, and honesty with oneself) to result from sessions, and Watts et al. (2017) reported increased connection to self and feeling more attuned with ones’ internal needs and inherent worth as central processes underlying transformative experiences, in previously depressed patients (Watts et al., 2017). For example, ‘One of the things that happened to me (…) was the magnification of how important it was to be true to yourself and have integrity about it’ (Noorani et al., 2018: 11).

Finally, regarding relatedness, Noorani et al. (2018) noted that sessions left participants with lasting impressions of interconnectedness and an increase in prosocial behaviour. ‘Relatedness’, as defined by SDT, is an especially interesting case vis à vis the evidence that significant psychedelic experiences are often associated with increased feelings of connectedness to others (Carhart-Harris et al., 2018; Watts et al., 2017). A sense of unity, which might be conceptualized as an ultimate level of relatedness, is one of the features of the mystical experience construct that is strongly affected by classic psychedelics (Johnson et al., 2019). Future research will be needed to investigate whether psychedelic experiences relate to changes in concepts central to SDT (e.g., need satisfaction and autonomous self-regulation), and to what extent these concepts may predict lasting behaviour change after a positive experience or therapeutic process.

Spontaneous health behaviour changes with psychedelics

As a result of these lessons [from psychedelic treatment for depression], there were some major lifestyle changes; nearly half of the sample reported improvements to diet, exercise, and cutting down on drinking alcohol. One described the improvement to his diet that happened after the dose as ‘life-changing’, although he was not sure how these changes came about as he did not receive direct ‘lessons’ about diet. (Watts et al., 2017: 13)

To our knowledge, no study has been conducted specifically to investigate lifestyle behaviours such as over-eating and physical activity in relation to psychedelic use. However, some studies have asked participants to report spontaneous changes in various areas of their lives, including in health behaviours, perhaps due to the fact that anecdotal accounts of these phenomena are not uncommon. In fact, it appears that the first studies in alcohol abuse were initiated precisely because of ad hoc observations by some users – notably Leo Zeff, a famous psychedelic clinician, regarding his own smoking cessation success after using a classic psychedelic (c.f. Johnson et al., 2017b). It is also interesting to note that, along with environmental concerns, healthy eating and living more healthfully were popular elements of psychedelic culture from the beginning, at least in some communities (Smith and Sternfield, 1970).

In a recent observational study, 380 ayahuasca users were interviewed face to face and asked about their health (including height and weight, allowing for calculation of their body mass index (BMI)) and also their physical activity, diet and yoga/meditation habits (Ona et al., 2019). These measures were then compared to data from the general population. Although limited by the cross-sectional nature of the data (e.g., confounding factors may be present), results showed that ayahuasca users had a mean BMI of 22.6 kg/m², well below the 30 kg/m² cut-off for obesity and clearly lower than that of the general Spanish population (around 26 kg/m² in 2016; World Health Organization, 2017a) and had a high fruit and vegetable consumption (60–75% ingesting 3–6 servings a day of each vs. 22–48% in the general population). As to physical activity, 55% reported being ‘as physically active as they wished’, a value that seems high but which cannot be compared with any standard measure of activity in the population (Ona et al., 2019).

In a US survey of 343 people who claimed to have stopped or reduced alcohol consumption and misuse after a psychedelic experience, 63% of the participants also endorsed ‘improved diet,’ and 55% reported ‘increased exercise’ as a result of their psychedelic experience (Garcia-Romeu et al., 2019b). In a similar study of 444 participants who claimed to have stopped or reduced cannabis, opioid or stimulant misuse after a psychedelic experience, 59% endorsed ‘improved diet’ and 58% endorsed ‘increased exercise’ as a result of their psychedelic experience (Garcia-Romeu et al., 2019a). It is unknown from these studies whether these individuals were intentionally seeking changes in these specific areas as they embarked on psychedelic use. However, one can speculate that many were probably not because only 9.9% reported an intention to reduce/quit drinking alcohol. This suggests that psychedelic-assisted interventions that more specifically target health behaviour changes could result in even higher rates of success in this domain.

The Johns Hopkins’ studies on smoking cessation also provide some evidence that participants were making other positive changes in their lives (besides reducing smoking) as they went through the psilocybin-assisted therapy programme. Both the initial (Johnson et al., 2014) and follow-up (Johnson et al., 2017a) studies report significant (51%) increases in a self-reported scale titled ‘positive behaviour changes’ as people moved from baseline to the end of the treatment. These were described further in a qualitative analysis, which reported increases in time spent in nature, taking time for oneself, prosocial behaviours such as volunteering and joining community groups, and greater engagement with art (Noorani et al., 2018). A similar pattern was observed in the study of psilocybin for depression in cancer patients, from the same research group (Griffiths et al., 2016). Although these are not health-related behaviours per se, results suggest psychedelics may be associated with life changes consistent with improved well-being and meaning. In support of this, a recent 4.5 year follow-up of cancer patients who underwent psilocybin-assisted therapy showed persisting increases in not just well-being/life satisfaction (reported by 86% of participants, n=12) but also in ‘positive behaviour changes’ attributed to the psilocybin experience (100% of participants, n=14) (Agin-Liebes et al., 2020).

A qualitative descriptive study with 16 participants who had been previously diagnosed with an eating disorder (ED, anorexia nervosa or bulimia nervosa) and were at various phases of illness and/or recovery investigated how having partaken in one or several ayahuasca ceremonies influenced their management of their condition or recovery process (Lafrance et al., 2017). A majority of participants reported reductions in ED-related negative thoughts, improvements in emotional processing and regulation, and an increased ability to identify what they perceived as the root psychological causes of the disorder. No specific behavioural changes were measured, but participants generally either reported more easily managing symptoms or having achieved full and sustained remission, subsequent to their psychedelic experience.

Finally, a recent study looked at benefits and challenges in 278 users of microdosing with LSD and/or psilocybin (Anderson et al., 2019). Microdosing typically involves the regular (i.e., 2–3 times a week) intake of about 5–15% of the normal dose used in most studies. Consequently, both the brain/neurological effects as well as the psychological (and phenomenological) effects with this dosing model are presumed to be partially different than those from taking a high dose (Passie, 2019). These differences notwithstanding, and also considering other limitations (self-selected convenience sample with no comparison group), microdosing was associated with spontaneous improvements in meditative practice (49.1% of participants), exercise (49.1%), eating habits (36.0%) and sleep (28.8%); and with reduced use of caffeine (44.2%), alcohol (42.3%) and tobacco (21.0%).

From addiction to behaviour change interventions using psychedelics

Among the mental health/psychiatric targets of early clinical psychedelic research in the 1950s and 60s were disorders primarily defined by behavioural problems, including substance abuse disorders (e.g., alcohol, opioids). Surveying studies from the 1950s to 1970s, a meta-analysis of six double-blind intervention studies using LSD for alcohol misuse suggested a significant effect in abstinence rates at the short (2–3 months) and the medium-term (6 months), but not at 12 months (Krebs and Johansen, 2013). This line of research was resumed more recently, and results have tended to confirm the earlier observations with psilocybin for alcohol dependence (Bogenschutz et al., 2015), and extended it to tobacco smoking (Johnson et al., 2014, 2017b). In the latter studies, after two or three drug sessions and behaviour therapy before and after, biologically verified smoking abstinence at 12 months and ~30 months by far surpassed success rates in current treatment modalities (Johnson et al., 2017a). A complementary survey describes instances in which classic psychedelic use outside of research settings is followed by cessation or reduction of tobacco smoking (Johnson et al., 2017b).

Mechanisms of action in tobacco cessation with psychedelics reportedly include improved mood and affect, change in life priorities and values, motivational insights and emotional regulation (Johnson et al., 2017b). In addition, qualitative analysis of smoking cessation participants suggested psilocybin sessions helped in smoking abstinence by providing insights into self-identify and personal reasons for smoking, a sense of awe, curiosity and interconnectedness, and a persistent overshadowing of withdrawal symptoms (Noorani et al., 2018). It is noteworthy that for both smoking and alcohol dependence the most recent intervention trials using psychedelics have employed mainstream motivational/behaviour change methods such as Motivational Interviewing (Nielson et al., 2018) and Cognitive Behavioural Therapy (Johnson et al., 2014) to complement the substance-induced psychedelic experience(s). Both Motivational Interviewing and Cognitive Behavioural Therapy have been used extensively in the areas of mental health and health behaviour change (e.g., Frost et al., 2018; Health Quality Ontario, 2019).

The models of psychedelic therapy which are now emerging in the field (e.g., Watts and Luoma, 2020; Wolff et al., 2020) typically include one or two sessions where participants ingest the psychedelic compound (e.g., a psilocybin capsule), with variable amounts of preparation and integration therapeutic sessions (Johnson et al., 2008). Trained guides/therapists are usually present for the duration of the psychedelic experience. One reference is the use of psilocybin for smoking cessation at Johns Hopkins (Johnson et al., 2014, 2017a), where participants underwent a 15-week programme with six preparation/integration individual meetings. Psychedelic-assisted behavioural change interventions could also take place in a group format, which is often used in ceremonial settings, and holds much promise as a cost-effective way to deliver psilocybin therapy in research contexts. Although current lifestyle behaviour change interventions (e.g., for weight loss or diabetes) involve a wide variability of formats and length, a programme of several weeks (sometimes months) with regular educational sessions in a group setting is a very common model (e.g., Teixeira et al., 2010).

Looking forward, the therapeutic container for such work could be the ACE model (Accept, Connect, Embody) which was used to support patients undergoing psilocybin treatment for depression (Watts and Luoma, 2020) and is based on Acceptance and Commitment Therapy or ACT (A-Tjak et al., 2015). In fact, Walsh and Thiessen (2018)have also proposed that psychedelic therapy should incorporate Acceptance and Commitment Therapy, a framework which has also been used for different mental and physical health problems, including obesity (Lawlor et al., 2020) and depression (Bai et al., 2020). Alternatively, as highlighted above, Cognitive Behavioural Therapy (see also Wolff et al., 2020) and Motivational Enhancement Therapy (including Motivational Interviewing) could be used as therapeutic containers, as each of these has been supported by robust research as effective in supporting multiple varieties of health behaviour change (Miller and Rollnick, 2012). Motivational Interviewing in particular is largely consistent with SDT (Patrick and Williams, 2012), and both have a range of intervention techniques (e.g., Teixeira et al., 2020) which could be tested as part of future psychedelic-assisted behaviour change interventions.

Final considerations

We have reviewed the modern resurgence in psychedelic research with a focus on therapeutic applications. Among these are the treatment of addictions (alcohol and tobacco) using psychedelics, which can be viewed as instances of health behaviour change facilitation. We have also briefly reviewed how biological effects of psychedelics may result in acute psychological effects, such as relaxed beliefs, that may have long-lasting effects on perspective and behaviour. In addition, we have proposed that SDT, which emphasizes autonomy, competence and relatedness, may be a useful framework to understand increases in internally driven motivation upon well-integrated psychedelic experiences. Finally, we propose directions for how psychedelic work in behaviour change may be conducted in the future, establishing several parallels between commonly used models, such as Cognitive Behavioural Therapy or Acceptance and Commitment Therapy, and emerging psychedelic-assisted therapies for tobacco cessation or depression (e.g., the ACE model). Another area for future enquiry is to examine the role of individual differences in suggestibility as well as drug-induced enhancements of suggestibility in moderating and mediating behavioural change (Carhart-Harris et al., 2015; Carhart-Harris and Friston, 2019).

One concern might be an impression by some in the public that administering psychedelics to patients might cause them to lose motivation for prior pursuits and for engagement in mainstream society, including abandonment of family responsibilities. We suspect such fears are driven not by the pharmacological effects of psychedelic drugs, but by their historical cultural association with the counterculture and their status as illicit drugs. The data that directly addresses these questions in clinical research do not show evidence for it. For example, Griffiths et al. (2006, 2011) examined ratings by community observers (i.e., family members, friends or co-workers with frequent contact with the participant) about the participant’s behaviours, attitudes and functioning. These were assessed before psilocybin administration and up to 2 or 14 months after psilocybin administration. Both studies showed significant long-term improvements as assessed by these community observers, suggesting that the intervention did not cause a general tendency for people to drop out of mainstream society or disengage with their families. The clinical studies reviewed have utilized preparation, monitoring and some form of integration (Johnson et al., 2008). As psychedelics move forward as possible approved therapeutics, to minimize the potential for societally disruptive effects it is important that clinicians observe appropriate clinical practice boundaries and not introduce counter-cultural or supernatural frameworks to patients in the context of psychedelic therapy (Johnson, 2020).

There are numerous future directions suggested by our framework. Studies should expand existing research to look at broader ranges of behavioural targets including diet, exercise and other ‘wellness behaviours’. If such research endeavours are also encouraging, this would further reinforce the already suggestive case that psychedelic therapy can be broadly applicable to behaviour change via transdiagnostic mechanisms. Future work should continue to conduct hypothesis-driven tests of the REBUS and other models that may be useful for bridging our understanding of how acute pharmacological effects translate into long-term behaviour changes. Empirical work should also address the role of therapy, for example, whether results are enhanced when psychedelic sessions are accompanied by explicit frameworks such as Cognitive Behavioural Therapy, Motivational Interviewing and the ACE model, versus psychedelic sessions with only general preparation, monitoring and follow-up discussion. Additionally, research should eventually compare these, and potentially other therapeutic models, in their ability to support psychedelic therapy for particular indications. From the broadest perspective, if psychedelic-assisted therapy is found to work through general processes, such as relaxed beliefs, psychological flexibility and self-determined motivation, this might be used to enhance behaviour change across a number of disorders and lifestyle challenges, and enhance the effects of multiple psychotherapeutic approaches. This would constitute a shift to a fuller transdiagnostic understanding of psychiatric disorders along a continuum with normative human behaviour and lifestyle challenges.

Introduction

Promoting healthy lifestyles is a major focus in public and private sectors, with a significant global wellness market. The field of health behavior change investigates the underlying theories, factors, and interventions in this area. Encouraging healthier living is crucial because unhealthy behaviors contribute to various disorders, including obesity, diabetes, depression, cancer, and cardiovascular disease, leading to substantial personal suffering and economic burdens. Healthy lifestyles and mental well-being are closely linked, and harmful choices, such as substance use, significantly contribute to premature mortality. Tobacco and alcohol use, in particular, account for a large portion of global deaths. Despite decades of public health efforts, issues like obesity and physical inactivity remain widespread.

Psychedelic compounds, such as LSD, psilocybin (found in "magic mushrooms"), and DMT (present in ayahuasca), may not initially appear as tools for health promotion. However, plants and fungi with psychedelic properties have been used for centuries in holistic healing practices. In the mid-20th century, scientific study of these compounds began, with many studies exploring their potential to enhance traditional psychotherapy. Early research suggested positive results in treating mood disorders and addictions. For instance, a review of 21 studies from 1949 to 1973 indicated that 79% of participants experienced improvement in depression with LSD and psilocybin treatment. This period saw over 40,000 patients participate in more than 1,000 published studies with encouraging outcomes. Around 1970, psychedelic research largely ceased due to new restrictive laws, limited drug access, shifts in public opinion, professional marginalization, and a lack of funding.

The 21st century has seen a resurgence of human research involving psychedelic compounds. This renewed interest is evident in media coverage, advocacy movements, and increased funding for clinical studies. Research on psychedelic-assisted psychotherapy is now underway or planned for various psychiatric conditions, including cancer-related distress, depression, anxiety, substance use disorders, obsessive-compulsive disorder, and eating disorders. Despite often involving small sample sizes, published results are largely promising. In the USA, the Food and Drug Administration (FDA) has granted "Breakthrough Therapy Designation" to psilocybin therapy for depression, expediting its development toward potential licensing. Substances like ketamine and MDMA, which can induce psychedelic-like effects, are also being studied for conditions like depression, post-traumatic stress disorder, and substance use. However, this review focuses specifically on "classic psychedelics" due to their distinct mechanisms of action.

How do psychedelics work? A summary of neurobiological findings

Classic psychedelics primarily act by stimulating the serotonin 2A receptor (5-HT2AR). While these compounds also affect other receptor types, their main action appears to be through 5-HT2AR activation. Psychedelics generally have a favorable safety profile and do not appear to have significant addiction potential. The primary risks are associated with the intensity of the altered state of consciousness they produce, especially at higher doses, which necessitates professional supervision.

Stimulating the 5-HT2AR increases the excitability of the neuron, making it more responsive to signals. These receptors are most concentrated on cortical layer V pyramidal neurons, which are crucial for integrating information in the brain. At a broader level, this increased excitability leads to a desynchronization of brain activity and an increase in the complexity and unpredictability of brain signals, which correlates with the intensity of subjective experiences in individuals. On a larger scale, the effects include the temporary disruption of major brain networks, an expansion of the brain's repertoire of high-frequency states, and enhanced communication between large-scale networks. At the anatomical level, psychedelics have also been observed to promote cortical synaptogenesis, a significant indicator of brain plasticity. The key question, however, is how these neurobiological effects contribute to the therapeutic actions of psychedelic therapy.

A recent model, known as REBUS (relaxed beliefs under psychedelics), directly addresses this question. Inspired by the hierarchical predictive processing model of brain function, which suggests the brain constantly updates its understanding of the world to minimize unexpected events, the REBUS model proposes that psychedelics reduce the rigidity of deeply held beliefs at various levels of brain function, particularly at the highest levels. This means that activity in brain areas associated with high-level predictive models, such as specific brain rhythms and the integrity of networks like the default-mode network, becomes less constrained. In simpler terms, this effect manifests as a felt relaxation of ingrained beliefs or assumptions about oneself, relationships, or the world in general. Many psychiatric disorders are characterized by rigid habits of mind, behaviors, and beliefs. Examples include the negative thought patterns in depression, strong cravings in addictions, specific fears in anxiety disorders, obsessions in obsessive-compulsive disorder, and fixed bodily beliefs in body image disorders. According to the REBUS model, psychedelics offer individuals a temporary release from these strong beliefs, creating a window of opportunity for change that can be utilized if combined with a commitment to therapeutic work.

The evidence suggests a link between neuroscientific findings and the behavioral changes that psychedelics may facilitate. The revision of high-level cognitive processes not only impacts internal experiences (thoughts and feelings) but may also lead to new exploratory behaviors consistent with perspectives and beliefs gained during or after the psychedelic experience. For example, a newfound appreciation for natural environments could prompt more time spent outdoors for physical activity or a shift towards more sustainable diet and shopping habits. Such an increase in behavioral exploration aligns with an increase in the "openness to experience" personality trait, which psilocybin has been shown to enhance. From a mechanistic viewpoint, research indicates that psychedelics can induce flexible thinking patterns across different cognitive domains, from basic perception to language and semantics. Psychedelics may also boost creative thinking during acute states, depending on the context of the experience. Therefore, it is reasonable to assume that the effects of psychedelics at multiple levels of cognitive function can result in long-term behavioral changes.

Could psychedelic experiences increase self-determination?

Self-determination, or perceived autonomy, describes the extent to which actions are genuinely chosen and supported by an individual's deepest reflections. Self-determined motivation consistently correlates with improved psychological well-being and greater engagement in various tasks and long-term behaviors. Consequently, this concept has been explored in health behavior change studies across areas such as dental hygiene, diet, exercise, obesity, diabetes, and tobacco cessation, generally showing positive results. This concept may offer a valuable psychological framework for understanding how psychedelics could support lifestyle changes, particularly from a motivational perspective.

According to Self-Determination Theory (SDT), self-determined motivation and behavior stem from the satisfaction of three fundamental psychological needs: competence, autonomy, and relatedness. Similar to how basic human needs are essential for survival and development, SDT proposes that competence (a sense of self-efficacy and confidence), autonomy (wholehearted self-endorsement of actions), and relatedness (a sense of connection to others) are innate psychological needs vital for mental health and growth. SDT suggests that humans are naturally inclined to engage in interesting activities, develop skills, seek social connections, and integrate internal and external experiences, provided these basic psychological needs are met. SDT also includes the concept of a "true" or "core" self, a notion that resonates with many personal accounts from participants in psychedelic therapy research.

It is hypothesized that psychedelics could plausibly influence competence, autonomy, and interpersonal relatedness. While direct evidence for these specific effects is currently limited, accounts from participants in research trials for depression, alcohol cessation, and smoking cessation suggest this possibility. Regarding competence, participants have described feeling increased confidence, motivation, resolve, and commitment to change. In relation to autonomy, insights into self-identity, a deeper connection to oneself, and a greater attunement to internal needs and inherent worth have been reported as central to transformative experiences in previously depressed patients. For instance, some describe a powerful realization of the importance of being true to oneself and acting with integrity.

Finally, concerning relatedness, some participants have reported lasting impressions of interconnectedness and an increase in prosocial behaviors after sessions. Relatedness, as defined by SDT, is particularly relevant given evidence that significant psychedelic experiences are often associated with enhanced feelings of connection to others. A sense of unity, which can be seen as the ultimate level of relatedness, is a key feature of the mystical experience commonly induced by classic psychedelics. Future research is needed to investigate whether psychedelic experiences are linked to changes in central SDT concepts, such as need satisfaction and autonomous self-regulation, and to what extent these concepts might predict lasting behavioral changes after a positive experience or therapeutic process.

Spontaneous health behaviour changes with psychedelics

No studies have specifically investigated lifestyle behaviors like overeating and physical activity in relation to psychedelic use. However, some studies have asked participants to report spontaneous changes in various aspects of their lives, including health behaviors. Anecdotal reports of these phenomena are not uncommon; in fact, early studies on alcohol abuse began due to observations by users, such as a famous psychedelic clinician who quit smoking after using a classic psychedelic. It is also notable that healthy eating and living were common themes within early psychedelic culture in certain communities, alongside environmental concerns.

In an observational study, 380 ayahuasca users were interviewed about their health, including body mass index (BMI), physical activity, diet, and yoga/meditation habits. Compared to general population data, ayahuasca users had a lower average BMI, high fruit and vegetable consumption, and a large percentage reported being as physically active as desired. While these cross-sectional data have limitations, they suggest positive health profiles.

Separate US surveys of individuals who reported stopping or reducing substance misuse after a psychedelic experience also indicated improvements in other health behaviors. Among those who reduced or quit alcohol, 63% also reported an "improved diet" and 55% reported "increased exercise." Similarly, among those who reduced cannabis, opioid, or stimulant misuse, 59% reported an "improved diet" and 58% reported "increased exercise." It is unclear from these studies whether these individuals intended to change these specific areas when they began psychedelic use, but the low percentage of those initially intending to quit drinking suggests many changes were unintentional. This implies that psychedelic-assisted interventions specifically targeting health behavior changes could achieve even higher success rates.

Studies on smoking cessation at Johns Hopkins also show that participants made other positive life changes beyond reducing smoking during their psilocybin-assisted therapy program. Both initial and follow-up studies reported significant increases in self-reported "positive behavior changes." These included spending more time in nature, engaging in self-care, increased prosocial behaviors like volunteering, joining community groups, and greater engagement with art. A similar pattern was observed in a study of psilocybin for depression in cancer patients. While these are not strictly health-related behaviors, the results suggest psychedelics may be associated with life changes consistent with improved well-being and meaning. A 4.5-year follow-up of cancer patients who underwent psilocybin therapy showed lasting increases in well-being and life satisfaction, along with positive behavior changes attributed to the experience.

A qualitative study with 16 participants diagnosed with eating disorders, who had undergone ayahuasca ceremonies, explored the influence on their condition or recovery. Most participants reported reductions in negative thoughts related to their eating disorder, improved emotional processing and regulation, and a greater ability to identify the root psychological causes of the disorder. While specific behavioral changes were not measured, participants generally reported easier symptom management or achieving full and sustained remission after their psychedelic experience.

Finally, a recent study examined the benefits and challenges experienced by 278 users of microdosing LSD and/or psilocybin. Microdosing involves regularly taking a very small fraction of a typical dose, and its effects are presumed to differ from higher doses. Despite limitations such as a self-selected sample, microdosing was associated with spontaneous improvements in meditative practice, exercise, eating habits, and sleep, and with reduced use of caffeine, alcohol, and tobacco.

From addiction to behaviour change interventions using psychedelics

Early clinical research on psychedelics in the mid-20th century focused on disorders characterized by behavioral problems, including substance use disorders like alcohol and opioid addiction. A meta-analysis of six studies from the 1950s to 1970s using LSD for alcohol misuse indicated a significant effect on abstinence rates in the short and medium term, though not at 12 months. This line of research has resumed more recently, with results generally confirming earlier observations for psilocybin in alcohol dependence and extending them to tobacco smoking. In the smoking cessation studies, two or three psychedelic sessions combined with behavioral therapy resulted in biologically verified abstinence rates at 12 and 30 months that far exceeded current treatment success rates. A complementary survey also describes instances where classic psychedelic use outside of research settings led to the cessation or reduction of tobacco smoking.

The mechanisms of action reported in tobacco cessation with psychedelics include improved mood and emotional regulation, changes in life priorities and values, and motivational insights. Qualitative analysis of smoking cessation participants suggested that psilocybin sessions provided insights into self-identity and personal reasons for smoking, a sense of awe, curiosity, and interconnectedness, and a persistent reduction of withdrawal symptoms. It is noteworthy that recent intervention trials for both smoking and alcohol dependence have integrated mainstream motivational and behavioral change methods, such as Motivational Interviewing and Cognitive Behavioral Therapy, to complement the psychedelic experience. Both of these therapeutic approaches have extensive research supporting their effectiveness in mental health and health behavior change.

Current models of psychedelic therapy typically involve one or two sessions where participants ingest the psychedelic compound, alongside varying amounts of preparation and integration therapy sessions. Trained guides or therapists are usually present throughout the psychedelic experience. For example, the Johns Hopkins smoking cessation program involved a 15-week program with six individual preparation and integration meetings in addition to the psychedelic sessions. Psychedelic-assisted behavioral change interventions could also take place in a group format, which is often used in ceremonial settings and shows promise as a cost-effective way to deliver therapy in research contexts. Although current lifestyle behavior change interventions (e.g., for weight loss or diabetes) vary widely in format and length, a multi-week program with regular educational sessions in a group setting is a common model.

Looking ahead, the ACE (Accept, Connect, Embody) model, based on Acceptance and Commitment Therapy (ACT), was used to support patients undergoing psilocybin treatment for depression and could serve as a therapeutic framework for this work. ACT has also been applied to various mental and physical health issues, including obesity and depression. Alternatively, Cognitive Behavioral Therapy and Motivational Enhancement Therapy (including Motivational Interviewing) could also be used as therapeutic frameworks, as robust research supports their effectiveness in diverse health behavior changes. Motivational Interviewing, in particular, aligns well with Self-Determination Theory, and both approaches offer a range of intervention techniques that could be tested within future psychedelic-assisted behavior change interventions.

Final considerations

This review has examined the modern resurgence in psychedelic research, focusing on therapeutic applications. The treatment of addictions, such as alcohol and tobacco dependence, using psychedelics is presented as an example of facilitating health behavior change. The discussion also briefly covered how the biological effects of psychedelics can lead to acute psychological changes, like relaxed beliefs, which may have lasting impacts on an individual's perspective and behavior. Furthermore, Self-Determination Theory (SDT), which emphasizes autonomy, competence, and relatedness, has been proposed as a useful framework for understanding increases in internally driven motivation following well-integrated psychedelic experiences. Finally, potential future directions for psychedelic work in behavior change were outlined, drawing parallels between commonly used models like Cognitive Behavioral Therapy (CBT) or Acceptance and Commitment Therapy (ACT) and emerging psychedelic-assisted therapies for conditions like tobacco cessation or depression. The role of individual differences in suggestibility and drug-induced enhancements of suggestibility in influencing behavioral change also warrants future investigation.

One concern sometimes raised by the public is the impression that administering psychedelics might cause patients to lose motivation for their previous pursuits or disengage from mainstream society, including abandoning family responsibilities. Such fears likely stem not from the pharmacological effects of the drugs themselves, but from their historical association with counterculture and their status as illicit substances. Data from clinical research directly addressing these questions do not support these concerns. Studies have examined ratings from community observers (e.g., family members, friends, co-workers) regarding participants' behaviors, attitudes, and functioning before and after psilocybin administration. These studies consistently showed significant long-term improvements as assessed by these observers, indicating that the intervention did not cause a general tendency for individuals to withdraw from mainstream society or their families. The clinical studies reviewed have emphasized the importance of preparation, monitoring during sessions, and some form of integration afterward. As psychedelics progress toward potential approval as therapeutics, it is vital for clinicians to adhere to appropriate professional practice boundaries and to avoid introducing counter-cultural or supernatural frameworks to patients within the context of psychedelic therapy, to minimize any potential for socially disruptive effects.

Numerous future research directions emerge from this framework. Studies should expand beyond addiction treatment to investigate a broader range of behavioral targets, including diet, exercise, and other "wellness behaviors." If such research also yields encouraging results, it would further strengthen the case that psychedelic therapy can be broadly applicable to behavior change through mechanisms that cut across different conditions. Future work should continue to conduct hypothesis-driven tests of models like REBUS and other frameworks that can help bridge the understanding of how acute pharmacological effects translate into long-term behavioral changes. Empirical research should also examine the role of therapy, for instance, by comparing whether results are enhanced when psychedelic sessions are accompanied by explicit frameworks such as CBT, Motivational Interviewing, and the ACE model, versus psychedelic sessions with only general preparation, monitoring, and follow-up discussion. Additionally, research should eventually compare the effectiveness of these and potentially other therapeutic models in supporting psychedelic therapy for specific indications. From a broader perspective, if psychedelic-assisted therapy is found to operate through general processes such as relaxed beliefs, psychological flexibility, and self-determined motivation, this could be used to enhance behavior change across various disorders and lifestyle challenges, and to strengthen the effects of multiple psychotherapeutic approaches. This would represent a shift towards a more comprehensive, transdiagnostic understanding of psychiatric disorders as lying along a continuum with normative human behavior and lifestyle challenges.

Psychedelics and Health Behavior Change

Introduction

Promoting healthy lifestyles is a major focus for public and private organizations. The wellness industry, dedicated to these efforts, is a significant global market. Central to this industry is the study of health behavior change, which explores theories, factors, and strategies for encouraging healthier habits. Unhealthy behaviors can increase the risk of serious conditions such as obesity, diabetes, depression, cancer, and heart disease, leading to substantial personal suffering and economic costs. Healthy lifestyles are closely connected to mental well-being, and unhealthy choices, particularly substance use, contribute significantly to early death. Tobacco and alcohol use, for example, account for about 15% of deaths worldwide. Despite decades of public health efforts, issues like obesity and physical inactivity remain widespread.

Psychedelic compounds, including LSD, psilocybin (found in "magic mushrooms"), and DMT (found in ayahuasca), may not seem like obvious tools for promoting healthier living. However, plants and fungi with psychedelic properties have been used for centuries for holistic healing of the body and mind. In the mid-20th century, the creation of synthetic mescaline, LSD, and psilocybin allowed scientists to systematically study their effects. Hundreds of studies were conducted, with many focusing on how psychedelics could enhance traditional psychotherapy. Positive outcomes were reported, especially in treating mood disorders and addictions. For instance, a review of studies from 1949 to 1973 on LSD and psilocybin for depression found that 79% of participants showed improvement. During this period, over 40,000 patients participated in more than 1,000 studies, with many encouraging results. Around 1970, psychedelic research largely stopped due to strict new laws, difficulty in accessing the drugs, a shift in public opinion, professional exclusion, and lack of funding.

The 21st century has seen a significant return of human research with psychedelic compounds. This revival is evident in widespread media coverage, advocacy groups, and increased funding for clinical research. Studies on psychedelic-assisted psychotherapy are now being published, planned, or are underway for various mental health conditions, including cancer-related distress, depression, anxiety, substance use disorders, obsessive-compulsive disorder, and eating disorders. While most of these studies have small sample sizes, the results are largely promising. In the USA, the FDA has given "Breakthrough Therapy Designation" to psilocybin therapy for depression, which speeds up its development for potential licensing. Substances like ketamine and MDMA (ecstasy), which can cause psychedelic-like effects, are also being studied for depression, PTSD, and substance use. MDMA has also received Breakthrough Therapy Designation for PTSD. However, this review will not cover ketamine and MDMA because they are not considered "classic psychedelics" due to their differing mechanisms of action.

How Do Psychedelics Work? A Summary of Neurobiological Findings

Classic psychedelics primarily activate a specific serotonin receptor in the brain, the 5-HT2A receptor. While other psychedelics may affect other receptors, activating 5-HT2AR appears essential to their main actions. Psychedelics have a favorable safety profile and a low potential for addiction. The main risks are related to the intensity of the altered state of consciousness they produce, especially at higher doses, and the necessity of professional supervision during these experiences.

Stimulating the 5-HT2AR makes neurons more excitable, meaning they are more responsive to incoming signals. These receptors are most concentrated on certain neurons in the brain's outer layer (cortex), which are crucial for processing information. This increased excitability leads to more complex and unpredictable brain activity at a population level. This effect correlates strongly with how intense the subjective experience feels to individuals. At a larger scale, psychedelics affect the brain's intrinsic networks, increasing the variety of brain states and enhancing communication between different networks. On an anatomical level, psychedelics have been observed to promote the formation of new connections between brain cells, which is an important sign of brain plasticity. The key question is how these effects relate to the potential therapeutic benefits of psychedelic therapy.

A recent model, called the ‘REBUS’ model (Relaxed Beliefs Under Psychedelics), directly addresses this question. Inspired by how the brain tries to understand its environment, the REBUS model suggests that psychedelics reduce the rigid influence of long-held beliefs or assumptions, especially those at higher levels of brain function. In simpler terms, this means that the brain's usual patterns, such as brain rhythms or the activity of certain brain networks (like the default-mode network), become less regulated. Subjectively, this feels like a relaxation of deep-seated beliefs about oneself, relationships, or the world in general. In many mental health conditions, thinking and behavior patterns, as well as beliefs, can become too fixed and influential. Examples include negative thinking in depression, strong cravings in addictions, specific fears in anxiety disorders, or particular obsessions in OCD. According to the REBUS model, psychedelics offer a break from these rigid beliefs, creating a window of opportunity for change that can be used if individuals are committed to therapeutic development.

The evidence suggests a potential link between the effects of psychedelics on the brain and changes in behavior. Revising high-level mental processes not only impacts emotions and thoughts but can also lead to new, exploratory behaviors that align with new beliefs gained during or after the psychedelic experience. For instance, a new appreciation for nature might lead someone to spend more time outdoors (e.g., walking in parks) or adopt more sustainable consumption and dietary habits. This increase in exploring new behaviors aligns with an increase in the personality trait "openness to experience," which psilocybin has been shown to enhance. From a scientific perspective, studies in psychology and neuroscience indicate that psychedelics can promote flexible thinking patterns in various cognitive areas, from basic perception to language and meaning. Psychedelics may also boost creative thinking during acute states, depending on the context of the experience. It is therefore reasonable to assume that the effects of psychedelics at multiple levels of thought processes can lead to long-term changes in behavior.

Could Psychedelic Experiences Increase Self-Determination?

Self-determination, or a sense of personal control, refers to the extent to which one fully supports their own actions after deep reflection. Motivation driven by self-determination is consistently linked to better psychological well-being and to engaging with and persisting in various tasks and long-term behaviors. As a result, this concept has been studied in health behavior change across areas like dental hygiene, diet, exercise, obesity, diabetes, and quitting tobacco, generally showing positive results. This concept may offer a valuable psychological framework for understanding how psychedelics could help with lifestyle changes, especially regarding motivation.

According to Self-Determination Theory (SDT), the foundation of self-determined motivation and behavior lies in satisfying three psychological needs: competence, autonomy, and relatedness. Similar to Maslow's five human needs for survival and development, SDT proposes that competence (feeling effective), autonomy (making choices freely), and relatedness (feeling connected to others) are innate and essential psychological needs for mental health and personal growth. The theory suggests that humans are naturally driven to engage in interesting activities, use their abilities, seek connections with social groups, and integrate their internal and external experiences into a unified whole. However, this only happens when these basic psychological needs are met. SDT also discusses the idea of a "true" or "core" self, a concept that resonates with many personal accounts from participants in psychedelic therapy research.

It is hypothesized that psychedelics could influence competence (a sense of self-efficacy and confidence), autonomy (wholehearted endorsement of one's actions), and interpersonal relatedness. Although direct evidence for these effects is currently limited, accounts from participants in research trials for depression, alcohol cessation, and smoking cessation suggest this could be true. Regarding competence, participants reported increased "confidence, motivation, and resolve" and "commitment to change." In terms of autonomy, insights into self-identity (e.g., discovering one's true self) were found to result from sessions, along with an increased connection to self and feeling more attuned with internal needs. For example, one participant noted the profound realization of the importance of being true to oneself.

Finally, regarding relatedness, sessions left participants with lasting impressions of interconnectedness and an increase in prosocial behavior. "Relatedness," as defined by SDT, is particularly interesting given that significant psychedelic experiences are often associated with increased feelings of connection to others. A sense of unity, which might be considered the highest level of relatedness, is a key feature of the "mystical experience" construct strongly affected by classic psychedelics. Future research is needed to investigate whether psychedelic experiences relate to changes in concepts central to SDT (e.g., need satisfaction and autonomous self-regulation) and how much these concepts might predict lasting behavior change after a positive experience or therapeutic process.

Spontaneous Health Behavior Changes with Psychedelics

As a result of insights gained during psychedelic treatment for depression, significant lifestyle changes were observed; nearly half of the participants reported improvements in diet, exercise, and reduced alcohol consumption. One person described their dietary changes as "life-changing" but was unsure how they came about since no direct "lessons" on diet were provided.

To date, no studies have specifically investigated lifestyle behaviors like overeating and physical activity in relation to psychedelic use. However, some studies have asked participants about spontaneous changes in various areas of their lives, including health behaviors, perhaps because anecdotal reports of such phenomena are common. In fact, early studies on alcohol abuse began due to casual observations by some users, such as the famous psychedelic clinician Leo Zeff, who noted his own success in quitting smoking after using a classic psychedelic. It is also interesting that, along with environmental concerns, healthy eating and living more healthfully were popular elements of psychedelic culture from its early days in some communities.

In a recent observational study, 380 ayahuasca users were interviewed about their health (including BMI) and their physical activity, diet, and yoga/meditation habits. These measures were then compared to data from the general population. Although limited by its cross-sectional nature (meaning other factors could be at play), the results showed that ayahuasca users had a mean BMI well below the obesity threshold and significantly lower than that of the general Spanish population. They also had high fruit and vegetable consumption. Regarding physical activity, 55% reported being "as physically active as they wished," a high value, though difficult to compare with standard population measures.

In a U.S. survey of 343 people who reported stopping or reducing alcohol consumption after a psychedelic experience, 63% also reported an "improved diet," and 55% reported "increased exercise" as a result of their experience. A similar study of 444 participants who stopped or reduced cannabis, opioid, or stimulant misuse after a psychedelic experience found that 59% reported "improved diet" and 58% reported "increased exercise." These studies do not reveal whether individuals intentionally sought these specific changes when they began using psychedelics. However, it can be speculated that many did not, as only 9.9% of those in the alcohol study reported an intention to reduce or quit drinking. This suggests that psychedelic-assisted interventions specifically targeting health behavior changes could lead to even higher success rates in this area.

The Johns Hopkins studies on smoking cessation also provide evidence that participants made other positive changes in their lives beyond reducing smoking as they underwent the psilocybin-assisted therapy program. Both the initial and follow-up studies reported significant (51%) increases in a self-reported scale titled "positive behavior changes" from the beginning to the end of treatment. A qualitative analysis further described these changes, including more time spent in nature, self-care, prosocial behaviors like volunteering and joining community groups, and greater engagement with art. A similar pattern was observed in the study of psilocybin for depression in cancer patients. Although these are not health-related behaviors in the strictest sense, the results suggest psychedelics may be linked to life changes consistent with improved well-being and a sense of purpose. Supporting this, a 4.5-year follow-up of cancer patients who received psilocybin-assisted therapy showed lasting increases not only in well-being/life satisfaction but also in "positive behavior changes" attributed to the psilocybin experience by 100% of participants.

Finally, a recent study examined the benefits and challenges experienced by 278 individuals who microdosed with LSD and/or psilocybin. Microdosing typically involves regularly taking about 5–15% of a normal dose. Consequently, the brain and psychological effects are presumed to be partly different from those of a high dose. Despite these differences and other limitations (such as a self-selected sample), microdosing was associated with spontaneous improvements in meditative practice (49.1% of participants), exercise (49.1%), eating habits (36.0%), and sleep (28.8%); it was also associated with reduced use of caffeine (44.2%), alcohol (42.3%), and tobacco (21.0%).

From Addiction to Behavior Change Interventions Using Psychedelics

Among the mental health and psychiatric conditions targeted by early clinical psychedelic research in the 1950s and 60s were disorders primarily defined by behavioral problems, including substance use (e.g., alcohol, opioids). A meta-analysis of six studies from the 1950s to 1970s using LSD for alcohol misuse suggested a significant positive effect on abstinence rates in the short and medium term, though not at 12 months. This research area resumed more recently, with results tending to confirm earlier observations for psilocybin in alcohol dependence and extending it to tobacco smoking. In the smoking cessation studies, after two or three drug sessions combined with behavioral therapy, biologically confirmed smoking abstinence at 12 and 30 months far exceeded success rates of current standard treatments. A complementary survey describes instances where classic psychedelic use outside of research settings was followed by stopping or reducing tobacco smoking.

Mechanisms of action in tobacco cessation with psychedelics reportedly include improved mood and emotions, changes in life priorities and values, insights into motivation, and better emotional regulation. Additionally, a qualitative analysis of smoking cessation participants suggested psilocybin sessions helped in abstinence by providing insights into self-identity and personal reasons for smoking, a sense of awe, curiosity, interconnectedness, and a lasting reduction of withdrawal symptoms. It is noteworthy that for both smoking and alcohol dependence, the most recent intervention trials using psychedelics have incorporated mainstream motivational and behavior change methods like Motivational Interviewing and Cognitive Behavioral Therapy to complement the psychedelic experience. Both Motivational Interviewing and Cognitive Behavioral Therapy have been widely used and supported by research in mental health and health behavior change.

The models of psychedelic therapy now emerging typically involve one or two sessions where participants take the psychedelic compound, with varying amounts of preparation and integration therapeutic sessions. Trained guides or therapists are usually present during the psychedelic experience. One example is the use of psilocybin for smoking cessation at Johns Hopkins, where participants completed a 15-week program with six individual preparation and integration meetings. Psychedelic-assisted behavioral change interventions could also take place in a group format, which is often used in ceremonial settings and shows promise as a cost-effective way to deliver psilocybin therapy in research. Although current lifestyle behavior change interventions (e.g., for weight loss or diabetes) vary widely in format and length, a common model involves a program of several weeks or months with regular educational sessions in a group setting.

Looking ahead, the therapeutic approach for this work could be the ACE model (Accept, Connect, Embody), which was used to support patients receiving psilocybin treatment for depression and is based on Acceptance and Commitment Therapy (ACT). Researchers have also proposed that psychedelic therapy should incorporate Acceptance and Commitment Therapy, a framework used for various mental and physical health problems, including obesity and depression. Alternatively, as mentioned previously, Cognitive Behavioral Therapy and Motivational Enhancement Therapy (including Motivational Interviewing) could be used as therapeutic frameworks. Each of these approaches is supported by robust research as effective in supporting many types of health behavior change. Motivational Interviewing, in particular, aligns well with Self-Determination Theory, and both offer various intervention techniques that could be tested in future psychedelic-assisted behavior change interventions.

Final Considerations

This review has examined the modern resurgence in psychedelic research with a focus on its therapeutic applications. Among these are the treatment of addictions (alcohol and tobacco) using psychedelics, which can be seen as examples of facilitating health behavior change. The review also briefly discussed how the biological effects of psychedelics can lead to acute psychological effects, such as relaxed beliefs, which may have lasting impacts on perspective and behavior. Additionally, it was proposed that Self-Determination Theory, which emphasizes autonomy, competence, and relatedness, may be a useful framework for understanding increases in internally driven motivation following well-integrated psychedelic experiences. Finally, suggestions were offered for how future psychedelic work in behavior change might be conducted, drawing parallels between commonly used models like Cognitive Behavioral Therapy or Acceptance and Commitment Therapy and emerging psychedelic-assisted therapies for conditions like tobacco cessation or depression. Another area for future inquiry is to examine how individual differences in suggestibility, and drug-induced increases in suggestibility, might influence behavioral change.

One concern for some in the public might be the impression that administering psychedelics could cause patients to lose motivation for their previous goals or disengage from mainstream society, including abandoning family responsibilities. Such fears are likely driven not by the pharmacological effects of psychedelic drugs themselves, but by their historical association with counterculture and their status as illicit drugs. Data from clinical research that directly addresses these questions show no evidence for such effects. For example, studies examined ratings by community observers (family members, friends, or co-workers with frequent contact with participants) regarding participant behaviors, attitudes, and functioning. These assessments were done before psilocybin administration and up to 2 or 14 months afterward. Both studies showed significant long-term improvements as assessed by these observers, suggesting that the intervention did not cause a general tendency for people to withdraw from mainstream society or their families. The clinical studies reviewed have all included preparation, monitoring, and some form of integration. As psychedelics progress towards potential approval as therapeutics, it is important for clinicians to maintain appropriate professional boundaries and not introduce counter-cultural or supernatural frameworks to patients within the context of psychedelic therapy, to minimize any potential for socially disruptive effects.

Numerous future directions are suggested by this framework. Studies should expand existing research to include a broader range of behavioral targets, such as diet, exercise, and other "wellness behaviors." If such research endeavors also prove encouraging, it would further strengthen the already suggestive case that psychedelic therapy can be widely applicable to behavior change through mechanisms that cut across different disorders. Future work should continue to test models like REBUS and other frameworks that can help connect our understanding of how acute pharmacological effects translate into long-term behavior changes. Empirical research should also address the role of therapy; for instance, whether results are improved when psychedelic sessions are accompanied by explicit frameworks such as Cognitive Behavioral Therapy, Motivational Interviewing, and the ACE model, versus psychedelic sessions with only general preparation, monitoring, and follow-up discussion. Additionally, research should eventually compare these and potentially other therapeutic models in their ability to support psychedelic therapy for specific conditions. From the broadest perspective, if psychedelic-assisted therapy is found to work through general processes, such as relaxed beliefs, psychological flexibility, and self-determined motivation, this could be used to enhance behavior change across many disorders and lifestyle challenges, and strengthen the effects of multiple psychotherapeutic approaches. This would represent a shift towards a more comprehensive understanding of psychiatric disorders along a continuum with normal human behavior and lifestyle challenges.

Psychedelics and Health Behavior Change

Introduction

Encouraging healthy lifestyles, including good diet, physical activity, and avoiding smoking or excessive drinking, has become a top priority in both public and private sectors. The wellness industry is now valued at trillions of dollars. A field of study called 'health behavior change' focuses on understanding and developing ways to help people adopt healthier habits. Promoting healthier living is crucial because unhealthy behaviors increase the risk of serious illnesses like obesity, diabetes, depression, cancer, and heart disease. These conditions cause immense personal suffering and place a heavy financial burden on society. Healthy lifestyles are also closely linked to mental well-being. Unhealthy choices, especially substance use, contribute significantly to early deaths. For instance, tobacco and alcohol use together account for about 15% of deaths worldwide. Despite decades of public health efforts, obesity and lack of physical activity remain very common globally.

Psychedelic compounds such as LSD, psilocybin (found in 'magic mushrooms'), and DMT (found in ayahuasca) may not seem like obvious tools for promoting healthier living. However, plants and fungi with psychedelic properties have been used by humans for thousands of years for healing the body and mind. In the mid-20th century, scientists began to carefully study these compounds. Hundreds of studies were conducted, and many focused on whether psychedelics could improve traditional psychotherapy. Positive results were reported for treating mood disorders and addictions. For example, a review of 21 studies from 1949 to 1973 on LSD and psilocybin for depression found that 79% of participants showed improvement as judged by doctors. During this time, over 40,000 patients took part in more than 1000 published studies on psychedelics, with many encouraging outcomes. Around 1970, psychedelic research stopped due to new laws that made research very difficult, limited access to the drugs, a change in public opinion, professional disapproval, and a lack of funding.

The 21st century has seen a rebirth of human research with psychedelic compounds. This can be seen in media coverage, advocacy groups, and increased funding for clinical research. Studies on psychedelic-assisted therapy are now being published, planned, or are underway for a range of mental health conditions. These include distress related to cancer, depression, anxiety, substance use disorders, obsessive-compulsive disorder, and eating disorders. Although most studies have involved small groups, the results are largely promising. In the USA, the Food and Drug Administration (FDA) has given psilocybin therapy for depression a 'Breakthrough Therapy Designation.' This speeds up its development for approval if certain conditions are met. Substances like ketamine and MDMA, which can cause psychedelic-like effects, are also being studied for depression, post-traumatic stress disorder (PTSD), and substance use. MDMA has also received Breakthrough Therapy Designation from the US FDA for treating PTSD. However, this discussion will not cover ketamine and MDMA, as they are not considered 'classic psychedelics' and work differently.

How do Psychedelics Work? A Summary of Brain Findings

Classic psychedelics directly affect a specific serotonin receptor in the brain, known as the 5-HT2A receptor. While most popular psychedelics also affect other receptors, activating the 5-HT2A receptor seems crucial to their main effects. Psychedelics are known to be relatively safe with low potential for harm, and they appear to have almost no addiction potential. The main risks come from the intensity of the altered state of consciousness they produce, especially at higher doses, and the need for professional supervision during these experiences.

When the 5-HT2A receptor is stimulated, it makes the brain's neurons more sensitive to incoming signals. These receptors are most common on important information-processing neurons in a specific layer of the brain's outer cortex. This increased sensitivity leads to more varied and unpredictable brain activity, which is closely linked to how intense the subjective experience feels in humans. At a larger scale, this means that major brain networks become less organized in their usual ways. There is also an increase in the number of different global brain states and more communication between these large brain networks. From a structural perspective, psychedelics have been shown to encourage the growth of new connections between brain cells, a key sign of the brain's ability to change and adapt. The important question, however, is how these brain effects relate to the potential healing power of psychedelic therapy.

A recent model, called the 'REBUS' model (Relaxed Beliefs Under Psychedelics), helps answer this question. It suggests that psychedelics reduce the brain's strong focus on its existing beliefs or assumptions, especially at the highest levels of brain function. In simpler terms, this means that the usual activity in brain areas that hold high-level models of reality becomes less rigid. This can be felt as a relaxation of deeply held beliefs about oneself, relationships, or the world in general. In many mental health conditions, thinking patterns, behaviors, and beliefs can become too fixed or 'too precise,' meaning they are strongly ingrained and hard to change. Examples include negative thinking in depression, specific cravings in addictions, certain fears in anxiety disorders, obsessions in OCD, and body image issues. According to the REBUS model, psychedelics offer a break from these rigid beliefs, creating a chance for change that can be used effectively when combined with a commitment to therapy.

The information above suggests a possible link between what is found in neuroscience and the behavioral changes that psychedelics might help bring about. Changing these high-level brain mechanisms can not only affect thoughts and feelings but may also lead to new behaviors that fit with new ideas and beliefs gained during or after the psychedelic experience. For example, a new appreciation for nature could lead to spending more time outdoors for physical activity or making more sustainable choices in shopping and diet. This increase in exploring new behaviors aligns with an increase in 'openness to experience,' a personality trait that has been shown to increase with psilocybin. From a scientific viewpoint, evidence from psychology and neuroscience shows that psychedelics can promote flexible thinking in different areas of cognition, from basic perception to language and meaning. Psychedelics may also boost creative thinking during the acute state, depending on the setting of the experience. It is therefore reasonable to believe that the effects of psychedelics at various levels of brain function could lead to lasting changes in behavior.

Could Psychedelic Experiences Increase Self-Determination?

Self-determination, or perceived autonomy, describes how much a person genuinely supports their own actions after deep thought. Motivation that comes from self-determination is consistently linked to better mental well-being and to engaging in and sticking with various tasks and long-term behaviors. Therefore, this idea has been explored in studies about changing health behaviors, such as dental hygiene, diet, exercise, obesity, diabetes, and quitting tobacco, with generally encouraging results. It is proposed that self-determination could be a valuable framework for understanding how psychedelics might help with lifestyle changes, especially from a motivational perspective.

According to self-determination theory (SDT), the basis of self-determined motivation and behavior comes from satisfying three basic psychological needs: competence, autonomy, and relatedness. Just as certain human needs might be vital for survival and development, SDT suggests that competence, autonomy, and relatedness are natural and essential psychological needs for mental health and growth. It proposes that people are naturally driven to engage in interesting activities, use their abilities, seek connections in social groups, and bring together their inner thoughts and social experiences into a unified whole. However, this happens only to the extent that these basic psychological needs are met. SDT also mentions the idea of a 'true' or 'core' self, which researchers and therapists working with psychedelics often connect to the personal stories shared by many participants.

It is hypothesized that psychedelics could influence competence (a sense of being effective and confident in one's abilities), autonomy (a full endorsement of one's actions), and interpersonal relatedness (feeling connected to others). Although there is no direct proof yet, accounts from participants in studies for depression, alcohol cessation, and smoking cessation suggest this could be true. Regarding competence, some studies reported categories like 'confidence, motivation and resolve' and 'commitment to change' as parts of participants' experiences. Other participants mentioned feeling more 'confident,' 'resilient,' and 'effective.' In terms of 'autonomy,' insights into self-identity (such as discovering one's true self and being honest with oneself) were found to result from sessions. Increased connection to oneself and feeling more in tune with inner needs and inherent worth were also reported as central to transformative experiences in previously depressed patients. For example, one person described, "One of the things that happened to me... was the magnification of how important it was to be true to yourself and have integrity about it."

Finally, regarding relatedness, sessions reportedly left participants with lasting feelings of interconnectedness and an increase in friendly social behavior. 'Relatedness,' as defined by SDT, is particularly interesting given the evidence that significant psychedelic experiences are often linked to increased feelings of connection to others. A sense of unity, which might be seen as the highest level of relatedness, is a key feature of the mystical experience that is strongly affected by classic psychedelics. Future research will need to explore whether psychedelic experiences are linked to changes in ideas central to SDT (like need satisfaction and self-driven behavior) and how much these ideas can predict lasting behavior change after a positive experience or therapy.

Spontaneous Health Behavior Changes with Psychedelics

As a result of insights gained from psychedelic treatment for depression, some major lifestyle changes occurred; nearly half of the participants reported improvements in diet, exercise, and cutting down on alcohol. One person described their dietary improvement after the dose as 'life-changing,' even though they were unsure how these changes happened since they did not receive direct 'lessons' about diet.

As far as is known, no study has specifically looked into lifestyle behaviors like overeating and physical activity in relation to psychedelic use. However, some studies have asked participants to report changes in various aspects of their lives, including health behaviors, perhaps because anecdotal stories of these phenomena are common. In fact, it appears that the first studies on alcohol abuse began precisely because of chance observations by some users—notably Leo Zeff, a famous psychedelic therapist, regarding his own success in quitting smoking after using a classic psychedelic. It is also interesting that healthy eating and living more healthfully were popular parts of psychedelic culture from its beginning, at least in some communities, along with environmental concerns.

In a recent observational study, 380 ayahuasca users were interviewed in person about their health (including height and weight to calculate their body mass index, BMI) and their physical activity, diet, and yoga/meditation habits. These measures were then compared to data from the general population. Although the study was limited because it looked at data from a single point in time (meaning other factors could have influenced the results), findings showed that ayahuasca users had an average BMI of 22.6 kg/m2. This is well below the 30 kg/m2 cut-off for obesity and clearly lower than that of the general Spanish population (around 26 kg/m2 in 2016). They also consumed a high amount of fruits and vegetables (60–75% ate 3–6 servings a day of each, compared to 22–48% in the general population). Regarding physical activity, 55% reported being 'as physically active as they wished,' a value that seems high but cannot be compared with standard measures of activity in the population.

In a US survey of 343 people who said they had stopped or reduced alcohol consumption and misuse after a psychedelic experience, 63% also reported an 'improved diet,' and 55% reported 'increased exercise' as a result of their psychedelic experience. In a similar study of 444 participants who said they had stopped or reduced cannabis, opioid, or stimulant misuse after a psychedelic experience, 59% reported 'improved diet' and 58% reported 'increased exercise.' It is unknown from these studies whether these individuals intended to change these specific areas when they began using psychedelics. However, it can be guessed that many probably did not, because only 9.9% reported an intention to reduce or quit drinking alcohol. This suggests that psychedelic-assisted interventions specifically aimed at health behavior changes could lead to even greater success rates in this area.

The Johns Hopkins' studies on smoking cessation also show that participants made other positive changes in their lives (besides reducing smoking) while undergoing psilocybin-assisted therapy. Both the initial and follow-up studies reported significant (51%) increases in a self-reported scale called 'positive behavior changes' as people progressed from the start to the end of treatment. These changes were further described in a detailed analysis, which noted increases in time spent in nature, taking time for oneself, pro-social behaviors like volunteering and joining community groups, and greater engagement with art. A similar pattern was seen in a study of psilocybin for depression in cancer patients by the same research group. While these are not strictly health-related behaviors, the results suggest psychedelics may be linked to life changes that lead to improved well-being and meaning. Supporting this, a recent 4.5-year follow-up of cancer patients who received psilocybin-assisted therapy showed lasting increases not only in well-being and life satisfaction (reported by 86% of participants) but also in 'positive behavior changes' attributed to the psilocybin experience (100% of participants).

A detailed study with 16 participants previously diagnosed with an eating disorder (anorexia nervosa or bulimia nervosa) who were at different stages of illness or recovery explored how participating in one or more ayahuasca ceremonies influenced their management or recovery process. Most participants reported fewer negative thoughts related to their eating disorder, improvements in processing and managing emotions, and a greater ability to identify what they saw as the underlying psychological causes of the disorder. No specific behavioral changes were measured, but participants generally reported either more easily managing symptoms or achieving full and lasting recovery after their psychedelic experience.

Finally, a recent study looked at the benefits and challenges for 278 people who used microdosing with LSD and/or psilocybin. Microdosing typically involves taking a very small dose (about 5–15% of a normal dose) regularly, usually 2–3 times a week. Because of this, the brain and psychological effects are thought to be partly different from those of a high dose. Despite these differences and other limitations (the study involved people who chose to participate, with no comparison group), microdosing was linked to spontaneous improvements in meditation practice (49.1% of participants), exercise (49.1%), eating habits (36.0%), and sleep (28.8%). It was also linked to reduced use of caffeine (44.2%), alcohol (42.3%), and tobacco (21.0%).

From Addiction to Behavior Change Interventions Using Psychedelics

Among the mental health conditions targeted by early clinical psychedelic research in the 1950s and 60s were disorders mainly defined by behavioral problems, including substance use (e.g., alcohol, opioids). A review of six studies from the 1950s to 1970s that used LSD to treat alcohol misuse suggested a notable effect on abstinence rates in the short term (2–3 months) and medium term (6 months), but not at 12 months. This area of research has recently restarted, and results have generally confirmed earlier findings with psilocybin for alcohol dependence and extended them to tobacco smoking. In the smoking cessation studies, after two or three drug sessions combined with behavior therapy before and after, biologically confirmed smoking abstinence at 12 months and about 30 months greatly surpassed success rates of current treatment methods. A related survey describes cases where classic psychedelic use outside of research settings was followed by stopping or reducing tobacco smoking.

The reported ways psychedelics help with tobacco cessation include improved mood and emotions, changes in life priorities and values, insights into motivation, and better emotional control. Additionally, a detailed analysis of smoking cessation participants suggested that psilocybin sessions helped them quit smoking by providing insights into self-identity and personal reasons for smoking, a sense of wonder and connection, and a lasting reduction of withdrawal symptoms. It is worth noting that for both smoking and alcohol dependence, the most recent intervention studies using psychedelics have used standard motivational and behavior change methods, such as Motivational Interviewing and Cognitive Behavioral Therapy. These methods are used to support the drug-induced psychedelic experiences. Both Motivational Interviewing and Cognitive Behavioral Therapy have been widely used in mental health and health behavior change.

The models of psychedelic therapy now emerging in the field typically involve one or two sessions where participants take the psychedelic compound (e.g., a psilocybin capsule), along with varying amounts of preparation and integration therapy sessions. Trained guides or therapists are usually present throughout the psychedelic experience. One example is the use of psilocybin for smoking cessation at Johns Hopkins, where participants completed a 15-week program with six individual preparation and integration meetings. Psychedelic-assisted behavioral change interventions could also happen in a group setting, which is often used in ceremonial contexts and shows great promise as a cost-effective way to provide psilocybin therapy in research. While current lifestyle behavior change interventions (e.g., for weight loss or diabetes) vary widely in format and length, a program lasting several weeks (sometimes months) with regular educational sessions in a group setting is a very common model.

Looking ahead, the 'ACE' model (Accept, Connect, Embody), which supports patients receiving psilocybin treatment for depression, could serve as a therapeutic framework for such work. This model is based on Acceptance and Commitment Therapy (ACT). It has also been proposed that psychedelic therapy should include Acceptance and Commitment Therapy, a framework used for various mental and physical health problems, including obesity and depression. Alternatively, Cognitive Behavioral Therapy and Motivational Enhancement Therapy (including Motivational Interviewing) could be used as therapeutic frameworks, as robust research supports their effectiveness in promoting many types of health behavior change. Motivational Interviewing, in particular, largely aligns with self-determination theory, and both have a range of intervention techniques that could be tested in future psychedelic-assisted behavior change interventions.

Final Considerations

This discussion has reviewed the recent comeback in psychedelic research, focusing on its uses in therapy. This includes the treatment of addictions (alcohol and tobacco) with psychedelics, which can be seen as examples of helping with health behavior change. It also briefly reviewed how the biological effects of psychedelics can lead to immediate psychological effects, such as relaxed beliefs, that may have lasting impacts on a person's outlook and behavior. In addition, it was suggested that self-determination theory, which highlights autonomy, competence, and relatedness, could be a useful way to understand how well-integrated psychedelic experiences can increase motivation that comes from within. Finally, directions for how future psychedelic work in behavior change might be conducted were proposed, drawing several comparisons between commonly used models, like Cognitive Behavioral Therapy or Acceptance and Commitment Therapy, and new psychedelic-assisted therapies for quitting tobacco or treating depression. Another area for future study is to examine how individual differences in suggestibility, as well as drug-induced increases in suggestibility, might influence behavior change.

Some in the public might worry that giving psychedelics to patients could cause them to lose motivation for their usual activities and disengage from mainstream society, including neglecting family responsibilities. Such fears are likely driven not by the drug's effects, but by its historical link to counterculture movements and its status as an illegal drug. The research data that directly addresses these concerns in clinical studies show no evidence of this. For instance, studies examined ratings by community observers (such as family members, friends, or co-workers who regularly interacted with participants) about their behaviors, attitudes, and functioning. These assessments were done before psilocybin was given and up to 2 or 14 months afterward. Both studies showed significant long-term improvements as judged by these observers, suggesting that the treatment did not cause people to drop out of society or become disengaged from their families. The clinical studies reviewed have all included preparation, monitoring, and some form of integration. As psychedelics move toward becoming approved treatments, it is important for clinicians to follow proper professional guidelines and not introduce counter-cultural or spiritual ideas to patients during psychedelic therapy, to reduce any potential for negative societal effects.

Many future directions are suggested by this framework. Studies should expand current research to look at a wider range of behavioral goals, including diet, exercise, and other 'wellness behaviors.' If such research also shows encouraging results, it would further strengthen the already compelling case that psychedelic therapy can be widely applied to behavior change through common underlying mechanisms. Future work should continue to test models like REBUS and others that can help explain how immediate drug effects lead to long-term behavior changes. Practical research should also address the role of therapy; for example, whether results are better when psychedelic sessions are combined with clear frameworks like Cognitive Behavioral Therapy, Motivational Interviewing, and the ACE model, versus psychedelic sessions with only general preparation, monitoring, and follow-up discussion. Additionally, research should eventually compare these, and possibly other therapeutic models, in their ability to support psychedelic therapy for specific conditions. From a broad view, if psychedelic-assisted therapy is found to work through general processes like relaxed beliefs, mental flexibility, and self-driven motivation, this understanding could be used to improve behavior change across various disorders and lifestyle challenges, and enhance the effects of many different psychotherapy approaches. This would represent a shift towards a more complete understanding of mental health conditions existing on a spectrum with normal human behavior and lifestyle challenges.

Summary

Helping people live healthier lives is very important. This includes eating better, being more active, and stopping excessive substance use. Many people want to make these changes. Unhealthy habits can lead to serious illnesses like heart disease and cancer, and cause a lot of suffering and cost. Mental health and healthy living are also closely connected.

Certain powerful substances, often called psychedelics, might seem like strange tools for health. However, plants and fungi with these effects have been used for thousands of years to heal the body and mind. In the middle of the last century, scientists began to study these substances like LSD and psilocybin (from "magic mushrooms"). They found promising results for mental health problems and addictions. For example, some studies showed many people with depression felt better after treatment. Research largely stopped around 1970 due to strict new laws, making the substances hard to get, and a shift in public opinion.

Now, in the 21st century, there is a new wave of research into psychedelics. More people are talking about them, groups are supporting studies, and more money is available for research. Studies are looking at how psychedelics, along with therapy, can help with cancer-related sadness, depression, anxiety, problems with drugs or alcohol, and other mental health issues. While most studies are still small, the results are largely good. In the USA, the FDA has given psilocybin therapy special fast-track status for depression, which means it could become an approved treatment sooner.

How Psychedelics Work

Classic psychedelics work on a special part of brain cells that uses serotonin, a brain chemical. This is key to how they affect the mind. These substances are quite safe and have a very low chance of addiction. The main risks come from the intense changes in thinking and feeling they cause, especially at higher amounts, which means a professional must be present.

When these substances activate the brain cells, they make them more active. This leads to less orderly brain activity and more complex brain signals. On a bigger scale, it changes how large brain networks work and creates more varied brain patterns. It can also help grow new connections in the brain, showing the brain's ability to change.

The REBUS model (which stands for "relaxed beliefs under psychedelics") suggests that psychedelics make old ideas or fixed beliefs less strong, especially the deep ones we have about ourselves or the world. In many mental health problems, people get stuck in rigid ways of thinking and behaving. For example, people with depression might always think negatively, or people with addiction might have very strong cravings. The REBUS model says psychedelics give a person a break from these strong, fixed ideas. This creates a chance for change, especially if combined with a plan to improve during therapy.

The brain changes caused by psychedelics can lead to changes in how a person thinks and feels about themselves. This might also lead to trying new things. For example, a new appreciation for nature could make someone spend more time outside or choose healthier food. This willingness to try new things fits with a personality trait called "openness to experience," which psilocybin has been shown to increase. Psychedelics can also help people think in new ways, improve creativity, and affect how they see things and use language. It makes sense that these effects could lead to lasting changes in behavior.

Can Psychedelics Help People Make Their Own Choices?

Feeling in control of one's choices, or "self-determination," means truly wanting to do what one does. When people feel self-determined, they are more likely to feel good mentally and stick with tasks and long-term goals. This idea has been studied in health, like with dental hygiene, diet, exercise, and stopping smoking, often with good results. This idea could be a helpful way to understand how psychedelics might help people change their lifestyle, especially when it comes to motivation.

According to Self-Determination Theory, three basic mental needs lead to feeling self-determined: feeling good at things, feeling able to make your own choices, and feeling connected to others. Just like we have basic needs for survival, these are seen as basic mental needs for good mental health and personal growth. The theory suggests that people naturally want to do interesting things, use their skills, feel close to others, and make sense of their inner feelings and how they connect with others. But this only happens if these basic mental needs are met. The theory also talks about a "true self," which often comes up in stories from people who have had psychedelic therapy.

Researchers think psychedelics might help with feeling capable, making one's own choices, and feeling connected to others. While there is no direct proof yet, stories from people in studies for depression, stopping alcohol, and stopping smoking suggest this. People have reported feeling more "confident," "strong," and "effective." For feeling in control of their choices, people found they gained insights into their true self and felt more honest with themselves. They also reported feeling more connected to themselves and their inner needs.

Lastly, regarding feeling connected to others, studies found that psychedelic sessions made people feel more connected to others and more willing to help them. A strong feeling of unity is also a key part of intense psychedelic experiences. Future studies need to check if psychedelic experiences truly lead to changes in these areas and if these changes lead to lasting behavior changes.

Health Changes That Just Happen with Psychedelics

People who use psychedelics sometimes report making healthy lifestyle changes without even planning to. For example, one person in a study for depression said their diet improved greatly after a psychedelic dose, even though they didn't get direct advice about diet. The first studies on alcohol problems with psychedelics actually began because some users noticed they stopped smoking after taking them. Also, healthy eating and living were big parts of psychedelic culture early on in some communities.

In a recent study, 380 people who used ayahuasca were asked about their health, including their weight, exercise, diet, and yoga/meditation habits. Compared to the general public, ayahuasca users had a healthy average weight, ate many fruits and vegetables, and many felt they were as active as they wanted to be.

Other studies found similar results. In a US survey of 343 people who said they stopped or cut down on alcohol after a psychedelic experience, 63% also reported a "better diet," and 55% reported "more exercise." In another study of 444 people who stopped or cut down on cannabis, opioids, or stimulants after a psychedelic experience, 59% reported a "better diet" and 58% reported "more exercise." It is not known if these people were trying to make these changes when they used psychedelics. This makes researchers wonder if psychedelic therapy aimed directly at health changes could be even more successful.

Studies at Johns Hopkins on stopping smoking also show that people made other positive life changes besides quitting smoking. They reported spending more time in nature, taking time for themselves, helping others, joining community groups, and enjoying art more. A similar pattern was seen in a study of psilocybin for depression in cancer patients. These changes suggest that psychedelics may be linked to life changes that lead to greater well-being and meaning. A recent follow-up study of cancer patients who had psilocybin therapy showed they continued to have better well-being and positive behavior changes years later.

Finally, a study looked at the benefits and challenges for 278 people who were "microdosing," meaning they took very small amounts of LSD or psilocybin regularly. Even with these small amounts, people reported improvements in meditation, exercise, eating habits, and sleep. They also reported using less caffeine, alcohol, and tobacco.

Psychedelics for Changing Habits and Overcoming Addiction

In the 1950s and 60s, early studies on psychedelics looked at using them for problems like alcohol and opioid addiction. A review of studies from that time on LSD for alcohol problems suggested it helped people stop drinking for 2-6 months. This research has started again, and recent results confirm earlier findings for psilocybin with alcohol problems and also for stopping tobacco smoking. In studies on smoking, after two or three sessions with the substance and therapy before and after, people had much higher success rates in quitting smoking for a year or more, compared to usual treatments. Other reports also describe people stopping or cutting down on tobacco use after using classic psychedelics outside of research settings.

People who stopped smoking with psychedelics often reported feeling better, changing their life goals, gaining new understanding about their motivations, and being better at managing their feelings. Also, people said the psilocybin sessions helped them quit smoking by giving them insights into their true self and reasons for smoking, a sense of wonder, curiosity, and feeling connected to everything. The sessions also made withdrawal symptoms less strong. It is important to note that recent studies on psychedelics for substance use problems have used common therapy methods, like Motivational Interviewing and Cognitive Behavioral Therapy (CBT), along with the psychedelic experience. These therapy methods have been shown to be helpful for mental health and changing health habits.

The way psychedelic therapy is now being set up often includes one or two sessions where a person takes the psychedelic substance. There are also many therapy sessions before and after to prepare the person and help them understand their experience. Trained guides or therapists are usually with the person during the psychedelic experience. For example, in the Johns Hopkins smoking cessation study, people had a 15-week program with six individual therapy meetings. Psychedelic therapy to change habits could also happen in a group setting, which is often done in traditional ceremonies and could be a good way to offer this therapy to more people. Many usual health programs for things like weight loss also use group sessions for weeks or months.

Looking ahead, a therapy approach called the ACE model (Accept, Connect, Embody) has been used to support people having psilocybin treatment for depression. This model is based on Acceptance and Commitment Therapy (ACT), which has been used for different mental and physical health problems like obesity and depression. Other helpful therapy approaches like Cognitive Behavioral Therapy (CBT) and Motivational Interviewing (MI) could also be used with psychedelics. These methods have strong research to show they help people change many different health habits. Motivational Interviewing especially fits well with Self-Determination Theory, and both offer many ways to help people change that could be tested with psychedelic-assisted therapy.

Important Points to Remember

This review looked at the new interest in psychedelic research, especially how these substances can be used to help people. This includes treating addictions like alcohol and tobacco, which are ways to help people change their health habits. The review also briefly explained how the effects of psychedelics on the brain can lead to immediate changes in thinking and feeling, like "relaxed beliefs," which might have lasting effects on how a person sees the world and acts. It was also suggested that Self-Determination Theory, which focuses on feeling in control, capable, and connected, could be a helpful way to understand how people become more motivated after a good psychedelic experience. Finally, ideas were shared for how future psychedelic work to change habits could be done, pointing out ways it is similar to common therapy models like CBT or ACT.

Some people might worry that taking psychedelics could make patients lose their drive for daily life, or give up on family duties. These fears are likely not based on how the substances actually work, but on old ideas linking them to counter-culture groups and their illegal status. Studies that have looked directly at these questions in real research do not show this. For example, studies where family members or friends rated participants' behavior showed lasting improvements after psilocybin use. This suggests the treatment did not make people drop out of mainstream life or neglect their families. The clinical studies talked about in this review have always included preparing patients, watching them closely during the experience, and helping them understand their experience afterward. As psychedelics move toward becoming approved treatments, it is important for doctors to follow proper rules and not bring in spiritual or counter-culture ideas to patients during therapy.

There are many things to study in the future based on these ideas. Studies should look at more types of habits to change, such as diet, exercise, and other "wellness behaviors." If these studies also show good results, it would further support the idea that psychedelic therapy can help with a wide range of behavior changes. Future work should also continue to test ideas about how the immediate effects of psychedelics lead to long-term changes in behavior. Studies should also look at the role of therapy: do people get better results if psychedelic sessions are combined with specific therapy approaches like CBT, MI, or the ACE model, compared to just general preparation and follow-up? Also, research should compare these different therapy models to see which works best for certain conditions with psychedelic therapy. Overall, if psychedelic therapy works through general processes like relaxing fixed beliefs, making the mind more flexible, and increasing self-determination, it could help people change habits for many different problems and make other types of therapy work better. This would be a big step toward understanding mental health problems and lifestyle challenges as connected parts of normal human behavior.