Associations between lifetime classic psychedelic use and markers of physical health

Therapeutic modulation of the kynurenine pathway in severe mental illness and comorbidities: A potential role for serotonergic psychedelics

Mounting evidence points towards a crucial role of the kynurenine pathway (KP) in the altered gut-brain axis (GBA) balance in severe mental illness (SMI, namely depression, bipolar disorder, and schizophrenia) and cardiometabolic comorbidities. Preliminary evidence shows that serotonergic psychedelics and their analogues may hold therapeutic potential in addressing the altered KP in the dysregulated GBA in SMI and comorbidities. In fact, aside from their effects on mood, psychedelics elicit therapeutic improvement in preclinical models of obesity, metabolic syndrome, and vascular inflammation, which are highly comorbid with SMI. Here, we review the literature on the therapeutic modulation of the KP in the dysregulated GBA in SMI and comorbidities, and the potential application of psychedelics to address the altered KP in the brain and systemic dysfunction underlying SMI and comorbidities. Psychedelics might therapeutically modulate the KP in the altered GBA in SMI and comorbidities either directly, via altering the metabolic pathway by influencing the rate-limiting enzymes of the KP and affecting the levels of available tryptophan, or indirectly, by affecting the gut microbiome, gut metabolome, metabolism, and the immune system. Despite promising preliminary evidence, the mechanisms and outcomes of the KP modulation with psychedelics in SMI and systemic comorbidities remain largely unknown and require further investigation. Several concerns are discussed surrounding the potential side effects of this approach in specific cohorts of individuals with SMI and systemic comorbidities.

Religion, Psychedelics, Risky Behavior, and Violence

Research has found that psychedelic use is associated with positive behavioral changes, however research has yet to explore the relationship between socio-cultural conditions on this relationship. This paper intends to fill this gap by testing the effects of religious participation and beliefs on the relationship between psychedelic use and behaviors. This study examines the relationship between Lifetime Classic Psychedelic Use (LCPU), different aspects of religion (such as salience and attendance), and the likelihood of committing a violent assault. The analysis uses pooled data from the National Survey of Drug Use and Health (NSDUH) from 2015 to 2019, with a sample size of 282,768. Binary logistic regression models conducted in Stata 17 reveal that LCPU and religion (salience and influence) are independently associated with reduced violence. Additionally, two-way interactions indicate that the association between risky behavior and violence is smaller among individuals with high levels of religious salience. Furthermore, a three-way interaction suggests that the association between risky behavior and violence is smaller for those who have used psychedelics, with the largest effect observed among individuals with high religious salience. These results show that religious factors can influence the relationship between psychedelic use and behaviors, with both attendance and salience operating simultaneously.

Diminished psychedelic returns on distress: Marital status and household size

Although the use of psychedelics to impact health has seen growth, little research has tested the effects of culture conditions on the relationship. More specifically, how does marital status and family size affect the relationship between psychedelics and health? This study tests the relationship between Lifetime Classic Psychedelic Use (LCPU), marital status, and household size (number of people living in a household) on levels of psychological distress in the past 30 days. This project uses pooled data from the National Survey of Drug Use and Health (NSDUH) (2010 to 2018) (N = 674,521). The Final sample size is determined by the dependent variable, psychological distress in the past month (n = 158,633). The analysis includes a series of nested logistic regression models conducted in Stata 17. Results indicate that LCPU is independently associated with better health, but the association between LCPU and health varies across levels of household size. Larger households are associated with higher levels of distress, which are then exacerbated among psychedelics users. Furthermore, three-way interactions reveal that the negative association between household size and distress gets larger among psychedelic users who are married, divorced, and widowed. Overall, results suggest that household size negatively impacts the association between LCPU and health, with those who are married, divorced, and widowed experiencing the worst outcomes.

A role for the serotonin 2A receptor in the expansion and functioning of human transmodal cortex

Integrating independent but converging lines of research on brain function and neurodevelopment across scales, this article proposes that serotonin 2A receptor (5-HT2AR) signalling is an evolutionary and developmental driver and potent modulator of the macroscale functional organization of the human cerebral cortex. A wealth of evidence indicates that the anatomical and functional organization of the cortex follows a unimodal-to-transmodal gradient. Situated at the apex of this processing hierarchy-where it plays a central role in the integrative processes underpinning complex, human-defining cognition-the transmodal cortex has disproportionately expanded across human development and evolution. Notably, the adult human transmodal cortex is especially rich in 5-HT2AR expression and recent evidence suggests that, during early brain development, 5-HT2AR signalling on neural progenitor cells stimulates their proliferation-a critical process for evolutionarily-relevant cortical expansion. Drawing on multimodal neuroimaging and cross-species investigations, we argue that, by contributing to the expansion of the human cortex and being prevalent at the apex of its hierarchy in the adult brain, 5-HT2AR signalling plays a major role in both human cortical expansion and functioning. Owing to its unique excitatory and downstream cellular effects, neuronal 5-HT2AR agonism promotes neuroplasticity, learning and cognitive and psychological flexibility in a context-(hyper)sensitive manner with therapeutic potential. Overall, we delineate a dual role of 5-HT2ARs in enabling both the expansion and modulation of the human transmodal cortex.

Impact of a Naturalistic Psychedelic Experience on Smoking: A Retrospective Survey

Tobacco use disorder is a major public health concern. The aim of this study was to investigate the impact of a psychedelic experience in a natural context on tobacco use. A retrospective online survey was conducted on 173 individuals who reported having had a psychedelic experience while being smokers. Demographic information was collected, and characteristics of the psychedelic experience, tobacco addiction and psychological flexibility were assessed. Mean number of cigarettes smoked per day, and proportion of individuals with high tobacco dependency significantly decreased between the three time points (p < .001). Participants who reduced or quit smoking had more intense mystical experiences during the psychedelic session (p = .01) and lower psychological flexibility before the psychedelic experience (p = .018). The increase in psychological flexibility post psychedelic session, and the personal motives for the psychedelic experience were significant positive predictors of smoking reduction or cessation (p < .001). Our results confirmed that a psychedelic experience in smoker individuals can be associated with smoking and tobacco dependency reduction and that the personal motives for the psychedelic session, the intensity of the mystical experience, and the increase of psychological flexibility following the psychedelic experience, are associated with smoking cessation or reduction.

Psychedelic use and psychiatric risks

RATIONALE

Research on psychedelics has recently shown promising results in the treatment of various psychiatric disorders, but relatively little remains known about the psychiatric risks associated with naturalistic use of psychedelics.

OBJECTIVE

The objective of the current study was to investigate associations between naturalistic psychedelic use and psychiatric risks.

METHODS

Using a sample representative of the US adult population with regard to sex, age, and ethnicity (N=2822), this study investigated associations between lifetime naturalistic psychedelic use, lifetime unusual visual experiences, and past 2-week psychotic symptoms.

RESULTS

Among respondents who reported lifetime psychedelic use (n=613), 1.3% reported having been told by a doctor or other medical professional that they had hallucinogen persisting perception disorder. In covariate-adjusted linear regression models, lifetime psychedelic use was associated with more unusual visual experiences at any point across the lifetime, but no association was observed between lifetime psychedelic use and past 2-week psychotic symptoms. There was an interaction between lifetime psychedelic use and family (but not personal) history of psychotic or bipolar disorders on past 2-week psychotic symptoms such that psychotic symptoms were highest among respondents who reported lifetime psychedelic use and a family history of psychotic or bipolar disorders and lowest among those who reported lifetime psychedelic use and no family history of psychotic or bipolar disorders.

CONCLUSIONS

Although the results in this study should be interpreted with caution, the findings suggest that lifetime naturalistic use of psychedelics might be associated with more unusual visual experiences across the lifetime, as well as more psychotic symptoms in the past 2 weeks for individuals with a family history of psychotic or bipolar disorders and the reverse for those without such a family history. Future research should distinguish between different psychotic and bipolar disorders and should also utilize other research designs (e.g., longitudinal) and variables (e.g., polygenic risk scores) to better understand potential cause-and-effect relationships.

Mechanisms and molecular targets surrounding the potential therapeutic effects of psychedelics

Psychedelics, also known as classical hallucinogens, have been investigated for decades due to their potential therapeutic effects in the treatment of neuropsychiatric and substance use disorders. The results from clinical trials have shown promise for the use of psychedelics to alleviate symptoms of depression and anxiety, as well as to promote substantial decreases in the use of nicotine and alcohol. While these studies provide compelling evidence for the powerful subjective experience and prolonged therapeutic adaptations, the underlying molecular reasons for these robust and clinically meaningful improvements are still poorly understood. Preclinical studies assessing the targets and circuitry of the post-acute effects of classical psychedelics are ongoing. Current literature is split between a serotonin 5-HT2A receptor (5-HT2AR)-dependent or -independent signaling pathway, as researchers are attempting to harness the mechanisms behind the sustained post-acute therapeutically relevant effects. A combination of molecular, behavioral, and genetic techniques in neuropharmacology has begun to show promise for elucidating these mechanisms. As the field progresses, increasing evidence points towards the importance of the subjective experience induced by psychedelic-assisted therapy, but without further cross validation between clinical and preclinical research, the why behind the experience and its translational validity may be lost.

Pattern breaking: a complex systems approach to psychedelic medicine

Recent research has demonstrated the potential of psychedelic therapy for mental health care. However, the psychological experience underlying its therapeutic effects remains poorly understood. This paper proposes a framework that suggests psychedelics act as destabilizers, both psychologically and neurophysiologically. Drawing on the 'entropic brain' hypothesis and the 'RElaxed Beliefs Under pSychedelics' model, this paper focuses on the richness of psychological experience. Through a complex systems theory perspective, we suggest that psychedelics destabilize fixed points or attractors, breaking reinforced patterns of thinking and behaving. Our approach explains how psychedelic-induced increases in brain entropy destabilize neurophysiological set points and lead to new conceptualizations of psychedelic psychotherapy. These insights have important implications for risk mitigation and treatment optimization in psychedelic medicine, both during the peak psychedelic experience and during the subacute period of potential recovery.

Psychedelics and workplace harm

This study aims to understand the relationship between Lifetime Classic Psychedelic Use (LCPU), employment status, and weekly work hours on levels of psychological distress. The data used for this analysis is pooled from the National Survey of Drug Use and Health (NSDUH) from 2008-2019 and includes a sample size of 484,732 individuals. The findings suggest that LCPU and being employed are independently associated with better health. Additionally, the results indicate that psychedelic use is associated with lower distress for those who are employed, volunteer, retired, or permanently disabled. However, those who are unemployed, full-time students, or homemakers may experience higher levels of distress with psychedelic use. Interestingly, the analysis also suggests that those who use psychedelics are working longer hours per week before experiencing an increase in stress. Overall, the study suggests that psychedelics are not likely to have a negative impact on employment outcomes.

Effects of serotonergic psychedelics on mitochondria: Transdiagnostic implications for mitochondria-related pathologies

The use of serotonergic psychedelics has gained increasing attention in research, clinical practice and society. Growing evidence suggests fast-acting, transdiagnostic health benefits of these 5-hydroxytryptamine 2A receptor agonists. Here, we provide a brief overview of their benefits for psychological, cardiovascular, metabolic, neurodegenerative, and immunological pathologies. We then review their effect on mitochondria including mitochondrial biogenesis, functioning and transport. Mitochondrial dysregulation is a transdiagnostic mechanism that contributes to the aforementioned pathologies. Hence, we postulate that psychedelic-induced effects on mitochondria partially underlie their transdiagnostic benefits. Based on this assumption, we propose new treatment indications for psychedelics and that the health benefits induced by psychedelics depend on patient-specific mitochondrial dysregulation.

Prevalence and associations of challenging, difficult or distressing experiences using classic psychedelics

Previous studies have investigated challenging, difficult, or distressing classic psychedelic experiences, but little is known about the prevalence and associations of such experiences. Using nationally representative data of the US adult population (N = 2822), this study examined the prevalence and associations of challenging, difficult, or distressing experiences using classic psychedelics, in a subsample of respondents who reported lifetime classic psychedelic use (n = 613). Of the 613 respondents who reported lifetime classic psychedelic use, the majority of them (59.1 %) had never had a challenging, difficult, or distressing experience using a classic psychedelic, but 8.9 % of respondents reported functional impairment that lasted longer than one day as a result of such experiences. Notably, 2.6 % reported seeking medical, psychiatric, or psychological assistance in the days or weeks following their most challenging, difficult, or distressing classic psychedelic experience. In covariate-adjusted regression models, co-use of lithium, co-use of other mood stabilizers, and six set and setting variables (no preparation, disagreeable physical environment, negative mindset, no psychological support, dose was too large, major life event prior to experience) were associated with the degree of difficulty; and co-use of lithium, co-use of other mood stabilizers, and three set and setting variables (negative mindset, no psychological support, major life event prior to experience) were associated with overall risk of harm. In summary, this study provides insight into the prevalence and associations of challenging, difficult, or distressing classic psychedelic experiences. The findings broadly correspond with findings from previous studies and can inform harm reduction efforts and future experimental research designs.

Ketamine and serotonergic psychedelics: An update on the mechanisms and biosignatures underlying rapid-acting antidepressant treatment

The discovery of ketamine as a rapid-acting antidepressant spurred significant research to understand its underlying mechanisms of action and to identify other novel compounds that may act similarly. Serotonergic psychedelics (SPs) have shown initial promise in treating depression, though the challenge of conducting randomized controlled trials with SPs and the necessity of long-term clinical observation are important limitations. This review summarizes the similarities and differences between the psychoactive effects associated with both ketamine and SPs and the mechanisms of action of these compounds, with a focus on the monoaminergic, glutamatergic, gamma-aminobutyric acid (GABA)-ergic, opioid, and inflammatory systems. Both molecular and neuroimaging aspects are considered. While their main mechanisms of action differ-SPs increase serotonergic signaling while ketamine is a glutamatergic modulator-evidence suggests that the downstream mechanisms of action of both ketamine and SPs include mechanistic target of rapamycin complex 1 (mTORC1) signaling and downstream GABAA receptor activity. The similarities in downstream mechanisms may explain why ketamine, and potentially SPs, exert rapid-acting antidepressant effects. However, research on SPs is still in its infancy compared to the ongoing research that has been conducted with ketamine. For both therapeutics, issues with regulation and proper controls should be addressed before more widespread implementation. This article is part of the Special Issue on "Ketamine and its Metabolites".

Linkages between Psychedelics and Meditation in a Population-Based Sample in the United States

There are neurophysiological and phenomenological overlaps between psychedelic and meditative states, but there is little evidence on how exposure to psychedelics might be associated with meditation-related variables. We assessed lifetime classic psychedelic use, ego dissolution during one's most intense experience using a classic psychedelic, and exposure to meditation in a representative sample (n = 953) of American adults. Those who reported experience with meditation were invited to complete a follow-up survey (n = 536, 92.1% response rate) measuring meditation-related variables. Models controlled for a range of potential confounds. Exposure to meditation was associated with lifetime classic psychedelic use and ego dissolution in covariate-adjusted models. In addition, among meditators, greater ego dissolution was associated with more frequent meditation practice. Both lifetime classic psychedelic use and ego dissolution were associated with enlightenment as motivation to practice meditation as well as lower likelihood of overall perceived barriers to meditation practice. Ego dissolution was positively associated with finding meditation more effective. Neither lifetime classic psychedelic use nor ego dissolution was associated with greater likelihood of meditation-related adverse effects. Taken together, results support potential synergy between psychedelics and meditation, but randomized controlled trials are necessary to establish safety and evaluate potential causal relationships.

Associations between MDMA/ecstasy use and physical health in a U.S. population-based survey sample

INTRODUCTION

3,4-Methylenedioxymethamphetamine (MDMA/"ecstasy") is an empathogen that can give rise to increased pleasure and empathy and may effectively treat post-traumatic stress disorder. Although prior research has demonstrated associations between ecstasy use and favorable mental health outcomes, the associations between ecstasy and physical health have largely been unexplored. Thus, the goal of this study was to examine the associations between ecstasy use and physical health in a population-based survey sample.

METHOD

This study utilized data from the National Survey on Drug Use and Health (2005-2018), a yearly survey that collects information on substance use and health outcomes in a nationally representative sample of U.S. adults. We used multinomial, ordered, and logistic regression models to test the associations between lifetime ecstasy use and various markers of physical health (self-reported body mass index, overall health, past year heart condition and/or cancer, past year heart disease, past year hypertension, and past year diabetes), controlling for a range of potential confounders.

RESULTS

Lifetime ecstasy use was associated with significantly lower risk of self-reported overweightness and obesity (adjusted relative risk ratio range: 0.55-0.88) and lower odds of self-reported past year heart condition and/or cancer (adjusted odds ratio (aOR): 0.67), hypertension (aOR: 0.85), and diabetes (aOR: 0.58). Ecstasy use was also associated with significantly higher odds of better self-reported overall health (aOR: 1.18).

CONCLUSION

Ecstasy shares protective associations with various physical health markers. Future longitudinal studies and clinical trials are needed to more rigorously test these associations.

Is psychedelic use associated with cancer?: Interrogating a half-century-old claim using contemporary population-level data

BACKGROUND

In 1967, concerns about the carcinogenic potential of psychedelics arose after a study reported chromosomal damage in human leukocytes following in vitro lysergic acid (LSD) exposure. Worries were further heightened by subsequent reports of leukemia and other cancers in LSD users. Additional investigations of psychedelics' effects on chromosomes were published over the next decade, with the majority suggesting these concerns were unfounded. However, the relationship between psychedelics and cancer has been explored only minimally from an epidemiological perspective.

AIMS

To determine whether associations exist between psychedelic use and either lifetime cancer or hematologic cancer diagnoses.

METHODS

We analyzed data from adult participants in the 2015-2019 administrations of the National Survey on Drug Use and Health for associations between lifetime use of psychedelics and lifetime diagnosis of either any cancer or hematologic cancer.

RESULTS

We identified no associations between lifetime psychedelic use and either lifetime cancer diagnosis or hematologic cancer diagnosis. Sub-analyses of lifetime lysergamide, phenethylamine, and tryptamine use also revealed no associations with lifetime cancer or hematologic cancer diagnosis.

CONCLUSIONS

While laboratory studies and case reports from the 1960s and 1970s generated concerns about psychedelics' carcinogenic potential, this analysis of recent epidemiological data does not support an association between psychedelic use and development of cancer in general or hematologic cancer. Important study limitations to consider include a lack of information about psychedelic dosage, number of lifetime psychedelic exposures, and the temporal relationship between psychedelic use and cancer diagnosis.

Association between Lifetime Classic Psychedelic Use and Sick Leave in a Population-Based Sample

OBJECTIVES

Absenteeism from work due to illness, and related costs, has increased steadily during the past decades. In recent years, there has been a reemergence of research on the therapeutic effects of classic psychedelics showing associations with both physical and mental health. However, the association between classic psychedelics and sick leave remains unknown. The aim of this study is to investigate the association between lifetime classic psychedelic use and sick leave in the past 30 days among adults in the United States (N = 407,717), using data from the National Survey on Drug Use and Health (2005-2019), weighted to be representative of the US adult population.

METHODS

The primary analysis was conducted using multiple linear regression, controlling for sociodemographic characteristics, risky behavior, and use of other substances.

RESULTS

There was a significant and negative association between lifetime classic psychedelic use and sick leave in the past 30 days (B = -0.09, p < 0.01) when adjusting for all control variables.

CONCLUSION

These findings suggest that classic psychedelics could potentially lead to reduced sick leave and associated costs in the general population, but more research is needed to investigate potential causal pathways of classic psychedelics on sick leave and evaluate possible mechanisms.

Psychedelic drug abuse potential assessment research for new drug applications and Controlled Substances Act scheduling

New medicines containing classic hallucinogenic and entactogenic psychedelic substance are under development for various psychiatric and neurological disorders. Many of these, including psilocybin, lysergic acid diethylamide (LSD), and 3,4-methylenedioxymethamphetamine (MDMA) are Schedule I controlled substances of the United States Controlled Substances Act (US CSA), and similarly controlled globally. The implications of the CSA for research and medicines development, the path to approval of medicines, and their subsequent removal from Schedule I in the US are discussed. This entire process occurs within the framework of the CSA in the US and its counterparts internationally in accordance with international drug control treaties. Abuse potential related research in the US informs the eight factors of the CSA which provide the basis for rescheduling actions that must occur upon approval of a drug that contains a Schedule I substance. Abuse-related research also informs drug product labeling and the risk evaluation and mitigation strategies (REMS) will likely be required for approved medicines. Human abuse potential studies typically employed in CNS drug development may be problematic for substances with strong hallucinogenic effects such as psilocybin, and alternative strategies are discussed. Implications for research, medicinal development, and controlled substance scheduling are presented in the context of the US CSA and FDA requirements with implications for global regulation. We also discuss how abuse-related research can contribute to understanding mechanisms of action and therapeutic effects as well as the totality of the effects of the drugs on the brain, behavior, mood, and the constructs of spirituality and consciousness.

Acute and long-term effects of psilocybin on energy balance and feeding behavior in mice

Psilocybin and other serotonergic psychedelics have re-emerged as therapeutics for neuropsychiatric disorders, including addiction. Psilocybin induces long-lasting effects on behavior, likely due to its profound ability to alter consciousness and augment neural connectivity and plasticity. Impaired synaptic plasticity in obesity contributes to 'addictive-like' behaviors, including heightened motivation for palatable food, and excessive food seeking and consumption. Here, we evaluate the effects of psilocybin on feeding behavior, energy metabolism, and as a weight-lowering agent in mice. We demonstrate that a single dose of psilocybin substantially alters the prefrontal cortex transcriptome but has no acute or long-lasting effects on food intake or body weight in diet-induced obese mice or in genetic mouse models of obesity. Similarly, sub-chronic microdosing of psilocybin has no metabolic effects in obese mice and psilocybin does not augment glucagon-like peptide-1 (GLP-1) induced weight loss or enhance diet-induced weight loss. A single high dose of psilocybin reduces sucrose preference but fails to counter binge-like eating behavior. Although these preclinical data discourage clinical investigation, there may be nuances in the mode of action of psychedelic drugs that are difficult to capture in rodent models, and thus require human evaluation to uncover.

Antidepressant effects of a psychedelic experience in a large prospective naturalistic sample

BACKGROUND

Over the last two decades, a number of studies have highlighted the potential of psychedelic therapy. However, questions remain to what extend these results translate to naturalistic samples, and how contextual factors and the acute psychedelic experience relate to improvements in affective symptoms following psychedelic experiences outside labs/clinics. The present study sought to address this knowledge gap.

AIM

Here, we aimed to investigate changes in anxiety and depression scores before versus after psychedelic experiences in naturalistic contexts, and how various pharmacological, extrapharmacological and experience factors related to outcomes.

METHOD

Individuals who planned to undergo a psychedelic experience were enrolled in this online survey study. Depressive symptoms were assessed at baseline and 2 and 4 weeks post-psychedelic experience, with self-rated Quick Inventory of Depressive Symptomatology (QIDS-SR-16) as the primary outcome. To facilitate clinical translation, only participants with depressive symptoms at baseline were included. Sample sizes for the four time points were N = 302, N = 182, N = 155 and N = 109, respectively.

RESULTS

Relative to baseline, reductions in depressive symptoms were observed at 2 and 4 weeks. A medicinal motive, previous psychedelic use, drug dose and the type of acute psychedelic experience (i.e. specifically, having an emotional breakthrough) were all significantly associated with changes in self-rated QIDS-SR-16.

CONCLUSION

These results lend support to therapeutic potential of psychedelics and highlight the influence of pharmacological and non-pharmacological factors in determining response. Mindful of a potential sample and attrition bias, further controlled and observational longitudinal studies are needed to test the replicability of these findings.

Psychedelics in the treatment of unipolar and bipolar depression

This is a narrative review about the role of classic and two atypical psychedelics in the treatment of unipolar and bipolar depression. Since the 1990s, psychedelics experience a renaissance in biomedical research. The so-called classic psychedelics include lysergic acid diethylamide (LSD), psilocybin, mescaline and ayahuasca. Characteristic effects like alterations in sensory perception, as well as emotion- and self-processing are induced by stimulation of serotonin 2A receptors in cortical areas. The new paradigm of psychedelic-assisted psychotherapy suggests a therapeutic framework in which a safely conducted psychedelic experience is integrated into a continuous psychotherapeutic process. First randomized, controlled trials with psilocybin show promising efficacy, tolerability, and adherence in the treatment of unipolar depression. On the other hand, classic psychedelics seem to be associated with the induction of mania, which is an important issue to consider for the design of research and clinical protocols. So called atypical psychedelics are a heterogeneous group with overlapping subjective effects but different neurobiological mechanisms. Two examples of therapeutic value in psychiatry are 3,4-methyl​enedioxy​methamphetamine (MDMA) and ketamine. Since 2020 the ketamine enantiomer esketamine has been granted international approval for treatment-resistant unipolar depression, and also first evidence exists for the therapeutic efficacy of ketamine in bipolar depression. Whether psychedelics will fulfil current expectations and find their way into broader clinical use will depend on future rigorous clinical trials with larger sample sizes. A well-considered therapeutic and legal framework will be crucial for these substances to create new treatment settings and a potential paradigm shift.

Classic Psychedelics and Human-Animal Relations

Previous research has found associations between classic psychedelic use and nature-relatedness, but the link between classic psychedelic use and human−animal relations remains largely unexplored. Using data representative of the US adult population, with regard to age, sex and ethnicity (N = 2822), this pre-registered study assessed lifetime classic psychedelic use, ego dissolution during respondents’ most intense experience using a classic psychedelic, and three measures related to human−animal relations: speciesism, animal solidarity and desire to help animals. The results showed that lifetime classic psychedelic use was negatively associated with speciesism (β = −0.07, p = 0.002), and positively associated with animal solidarity (β = 0.04, p = 0.041), but no association was found with desire to help animals (β = 0.01, p = 0.542). Ego dissolution during the respondents’ most intense experience using a classic psychedelic was negatively associated with speciesism (β = −0.17, p < 0.001), and positively associated with animal solidarity (β = 0.18, p < 0.001) and desire to help animals (β = 0.10, p = 0.007). The findings indicate that classic psychedelics and ego dissolution may have an impact on human−animal relations. As these results cannot demonstrate causality, however, future studies should use longitudinal research designs to further explore the potential causal link between classic psychedelic use and human−animal relations.

Ayahuasca and Public Health II: Health Status in a Large Sample of Ayahuasca-Ceremony Participants in the Netherlands

Ayahuasca is a plant decoction in traditional Amazonian medicine. Its ritual use has been internationalized, leading to policy challenges that countries should address. This study evaluates the impact of regular ayahuasca ceremony participation on health by assessing the health status of 377 participants in ayahuasca ceremonies in the Netherlands using validated health indicators. A questionnaire was developed and administered to study participants. The questionnaire included several health indicators with public health relevance (e.g., BMI, diet, physical activity) and psychometrically validated questionnaires (ELS and COPE-easy). The data retrieved through health indicators was compared to normative Dutch data. Participants (50.1% women) were mostly Dutch (84.6%) with a mean age of 48.8 years (SD = 11.6). Compared to normative Dutch data, regular participants in ayahuasca ceremonies showed better general well-being, fewer chronic or lifestyle-related diseases, more physical activity, and a more balanced diet. Participants also used less alcohol during the COVID-19 pandemic, and although they used more illegal drugs than the general population, they did not report associated harms. Our findings suggest that regular participation in ayahuasca ceremonies is not linked to relevant health harms. This data could help drug policymakers to develop and implement evidence-based public policies.

Exploring protective associations between the use of classic psychedelics and cocaine use disorder: a population-based survey study

Cocaine Use Disorder (CUD) is a significant public health problem associated with elevated morbidity and mortality within the United States. Current behavioral treatments have limited efficacy and there are currently no FDA approved pharmacological treatments for CUD. Classic psychedelics might be associated with lowered odds of substance misuse and may effectively treat various forms of addiction. Thus, the goal of this study is to assess protective associations that lifetime use of classic psychedelics may share with CUD within a nationally representative sample of the U.S. We used data from The National Survey on Drug Use and Health (NSDUH) (2015–2019) and conducted survey-weighted multivariable logistic regression to test whether each of four classic psychedelics (peyote, mescaline, psilocybin, LSD) conferred lowered odds of CUD and its related 11 sub-criteria. Participants were 214,505 adults in the NSDUH (2015–2019) aged 18 and older. Peyote conferred lowered odds of CUD, reducing the odds of CUD by over 50% (aOR: 0.47). All other substances (including other classic psychedelics) either shared no association to CUD or conferred increased odds of CUD. Furthermore, sensitivity analyses revealed peyote to confer sharply lowered odds of the majority (seven of 11) of CUD criteria as well (aOR range: 0.26–0.47). Peyote use is associated with lowered odds of CUD. Future inquiries into third variable factors (i.e., demographic/personality profiles of individuals who use peyote, motivational/contextual factors surrounding peyote use) that may underlie our observed associations may reveal protective factors that can inform treatment development for CUD. Additionally, future longitudinal studies can shed further light on whether there is a temporal link between peyote use and lowered odds of CUD.

Classic psychedelics, health behavior, and physical health

BACKGROUND

Preliminary evidence suggests that classic psychedelics may be effective in the treatment of some psychiatric disorders, yet little remains known about their effects on health behavior and physical health.

OBJECTIVES

The purpose of this study was to investigate associations of lifetime classic psychedelic use and psychological insight during one's most insightful classic psychedelic experience with health behavior and physical health.

METHODS

Using data representative of the US population with regard to sex, age, and ethnicity (N = 2822), this study examined associations of lifetime classic psychedelic use and psychological insight with health behavior and physical health.

RESULTS

Lifetime classic psychedelic use was associated with more healthy tobacco-related and diet-related behavior (β = 0.05 and 0.09, respectively). Among lifetime classic psychedelic users (n = 613), greater Psychological Insight Questionnaire (PIQ) total scale, PIQ Avoidance and Maladaptive Patterns (AMP) subscale, and PIQ Goals and Adaptive Patterns (GAP) subscale scores were each associated with higher odds of more healthy exercise-related behavior [adjusted odds ratios (aOR) (95% confidence interval, CI = 1.38 (1.13-1.68), 1.38 (1.13-1.68), and 1.32 (1.10-1.60), respectively] and higher odds of having a healthy body mass index (BMI) [aOR (95% CI) = 1.32 (1.07-1.63), 1.36 (1.10-1.69), and 1.23 (1.01-1.50), respectively], and greater GAP subscale scores were associated with more healthy diet-related behavior (β = 0.10). All PIQ scales were positively associated with some health behavior improvements (overall, diet, exercise) attributed to respondents' most insightful classic psychedelic experience (β = 0.42, 0.18, and 0.17; β = 0.40, 0.19, and 0.17; and β = 0.40, 0.15, and 0.15, respectively), but only PIQ total scale and AMP subscale scores were positively associated with alcohol-related health behavior improvements (β = 0.13 and 0.16, respectively).

CONCLUSION

Although these results cannot demonstrate causality, they suggest that psychological insight during a classic psychedelic experience may lead to positive health behavior change and better physical health in some domains, in particular in those related to weight management.

Lifetime use of MDMA/ecstasy and psilocybin is associated with reduced odds of major depressive episodes

BACKGROUND

Depression is a major mental health issue worldwide, with high rates of chronicity and non-recovery associated with the condition. Existing treatments such as antidepressant medication and psychological treatments have modest effectiveness, suggesting the need for alternative interventions.

AIM

The aim of this study was to examine the relationships between MDMA (3,4-methylenedioxymethamphetamine)/ecstasy and psilocybin use and major depressive episodes (MDEs).

METHODS

This observational study used data from a large (N = 213,437) nationally representative sample of US adults to test the association of lifetime use of MDMA/ecstasy, psilocybin and other classic psychedelics (lysergic acid diethylamide (LSD), peyote, mescaline), other illegal substances (e.g. cocaine, phencyclidine (PCP)), and legal/medicinal substances of misuse (e.g. pain relievers, tranquilizers) with lifetime, past year, and past year severe MDEs.

RESULTS

Results revealed that lifetime MDMA/ecstasy use was associated with significantly lowered odds of a lifetime MDE (adjusted odds ratio (aOR) = 0.84; p < 0.001), past year MDE (aOR = 0.84; p < 0.001), and past year severe MDE (aOR = 0.82; p < 0.001). Psilocybin was associated with significantly lowered odds of a past year MDE (aOR = 0.90; p < 0.05) and past year severe MDE (aOR = 0.87; p < 0.05). All other substances either shared no relationship with a MDE or conferred increased odds of an MDE.

CONCLUSIONS

These results suggest that MDMA/ecstasy and psilocybin use is associated with lower risk of depression. Experimental studies are needed to test whether there is a causal association between use of these compounds and the alleviation of depressive symptoms.

Chronic Treatment With Psilocybin Decreases Changes in Body Weight in a Rodent Model of Obesity

BACKGROUND

There are currently relatively few effective pharmacological treatments for obesity, and existing ones may be associated with limiting side-effects. In the search for novel anti-obesity agents, drugs that modify central serotonergic systems have historically proven to be effective in promoting weight loss. Psilocin, which is rapidly metabolized from psilocybin, is an agonist at multiple serotonin receptors. In the present study we assessed the effects of psilocybin and a positive control (metformin) on changes in body weight in a rat model of obesity.

METHODS

Five groups of adult male rats were pre-conditioned with a cafeteria diet until obese (>600 g) and then treated with either psilocybin (0.1, 1, or 5 mg/kg, i.p.), metformin (300 mg/kg, p.o.) or vehicle control. Treatments were for 27 consecutive weekdays, and body weights and high calorie food intake were recorded daily. Fasting glucose levels were recorded after 11 days of treatment. At the end of treatment rats completed a glucose tolerance test, and multiple fat pads were dissected out to assess adiposity.

RESULTS

The medium dose psilocybin group had to be terminated from the study prematurely. Both the low and high dose psilocybin groups caused a significant decrease in changes in body weight compared to controls. The metformin group produced a greater decrease in change in body weight than either psilocybin groups or controls. Both high dose psilocybin and metformin decreased consumption of the high calorie diet, and exhibited decreased central adiposity.

CONCLUSION

Psilocybin demonstrated modest but significant effects on weight gain. Further study is recommended.

Psychedelics, Sociality, and Human Evolution

Our hominin ancestors inevitably encountered and likely ingested psychedelic mushrooms throughout their evolutionary history. This assertion is supported by current understanding of: early hominins' paleodiet and paleoecology; primate phylogeny of mycophagical and self-medicative behaviors; and the biogeography of psilocybin-containing fungi. These lines of evidence indicate mushrooms (including bioactive species) have been a relevant resource since the Pliocene, when hominins intensified exploitation of forest floor foods. Psilocybin and similar psychedelics that primarily target the serotonin 2A receptor subtype stimulate an active coping strategy response that may provide an enhanced capacity for adaptive changes through a flexible and associative mode of cognition. Such psychedelics also alter emotional processing, self-regulation, and social behavior, often having enduring effects on individual and group well-being and sociality. A homeostatic and drug instrumentalization perspective suggests that incidental inclusion of psychedelics in the diet of hominins, and their eventual addition to rituals and institutions of early humans could have conferred selective advantages. Hominin evolution occurred in an ever-changing, and at times quickly changing, environmental landscape and entailed advancement into a socio-cognitive niche, i.e., the development of a socially interdependent lifeway based on reasoning, cooperative communication, and social learning. In this context, psychedelics' effects in enhancing sociality, imagination, eloquence, and suggestibility may have increased adaptability and fitness. We present interdisciplinary evidence for a model of psychedelic instrumentalization focused on four interrelated instrumentalization goals: management of psychological distress and treatment of health problems; enhanced social interaction and interpersonal relations; facilitation of collective ritual and religious activities; and enhanced group decision-making. The socio-cognitive niche was simultaneously a selection pressure and an adaptive response, and was partially constructed by hominins through their activities and their choices. Therefore, the evolutionary scenario put forward suggests that integration of psilocybin into ancient diet, communal practice, and proto-religious activity may have enhanced hominin response to the socio-cognitive niche, while also aiding in its creation. In particular, the interpersonal and prosocial effects of psilocybin may have mediated the expansion of social bonding mechanisms such as laughter, music, storytelling, and religion, imposing a systematic bias on the selective environment that favored selection for prosociality in our lineage.

Associations between lifetime classic psychedelic use and cardiometabolic diseases

The objective of the current study was to investigate the associations between lifetime classic psychedelic use and cardiometabolic diseases. Using data from the National Survey on Drug Use and Health (2005–2014), the present study examined the associations between lifetime classic psychedelic use and two types of cardiometabolic disease: heart disease and diabetes. Respondents who reported having tried a classic psychedelic at least once in their lifetime had lower odds of heart disease in the past year (adjusted odds ratio (aOR) = 0.77 (0.65–0.92), p = .006) and lower odds of diabetes in the past year (adjusted odds ratio (aOR) = 0.88 (0.78–0.99), p = .036). Classic psychedelic use might be beneficial for cardiometabolic health, but more research is needed to investigate potential causal pathways of classic psychedelics on cardiometabolic diseases.

Psychedelic Mushrooms in the USA: Knowledge, Patterns of Use, and Association With Health Outcomes

Introduction: Popular media coverage of psychedelics use, growing research into this class of compounds for psychiatry and decriminalization initiatives, are transforming the public perception of psychedelics. However, little is known about levels of knowledge and psychedelic mushroom (PM) use among American adults. Methods: We examined PM use and various measures of health status, quality of life, and self-reported mental health outcome measures obtained through a national on-line, cross-sectional survey of adults with a demographic composition representative of the US adult population by region, gender, age, and race (weighted N = 251,297,495) from November 2020-March 2021. Results: General mental health and well-being were popular reasons for PM use (63.6%), although use for medically-diagnosed (31.8%) and self-diagnosed (19.0%) conditions was also common. PM users reported more depression and anxiety as reflected in higher GAD-7 and PHQ-9 scores. Factors predictive of PM use included being male [OR 1.54 95%CI 1.09-2.15] and having higher Charlson Comorbidity Index scores [OR 1.42; 95%CI 1.22-1.65]. Self-reported PM use was less likely among participants with health insurance [OR = 0.50 (0.35-0.72)], increased age [OR = 0.92 (0.90-0.93)] and, relative to those living in the west US census region, living in the northeast [OR = 0.27 (0.15-0.50)], midwest [OR = 0.34 (0.20-0.56)], and south [OR = 0.38 (0.26-0.55)]. Discussion and Conclusions: A significant number of Americans are already "self-medicating" with PM and as growing positive media coverage of psychedelics drives public interest in the health benefits of PM, this number will increase. The association between PM use and poor mental health requires further research to inform policy.