"If you teach someone to meditate or to do yoga or to go on pilgrimage to some holy mountain, nothing is guaranteed to happen.  Yet if you are given 5 dried grams of magic mushrooms or DMT or some other potent psychedelic, whoever you are, a freight train of significance is going to be coming your way in a matter of moments."    Sam Harris

“Your assumptions are your window on the world. Scrub them off every once in a while, or the light won’t come in.”  Isaac Asimov

"For it appears to me that among the many exceptional and divine things your Athens has produced and contributed to human life, nothing is better than those (Eleusinian) mysteries.  For by means of them we have transformed from a rough and savage way of life to the state of humanity, and have been civilized.  Just as they are called initiations, so in actual fact we have learned from them the fundamentals of life, and have grasped the basis not only for living with joy but also for dying with a better hope."  Marcus Tullius Cicero  De Legibus 2.14.36

I have written two earlier blog posts - "Recent psychedelic research: introduction, mechanisms & risks" and "Recent psychedelic research: their use in psychotherapy".  Today I want to look at psychedelic use 'outside the treatment room'.  All around the world, over millennia, nearly every culture has used profoundly mind-altering substances in revered sacred rituals.  In Mexico & into North America there is mescaline & the peyote cactus (with archaeological evidence of use dating back over 5,000 years); in the Amazon region DMT & ayahuasca; all over the globe psilocybin & 'magic mushrooms'.  In ancient Greece, Crete & the Near East initiates of the Eleusinian Mysteries (and related ceremonies) - with their cycle of descent, search & ascent - drank kykeon, almost certainly psychoactive - maybe with ergot, a link to LSD. 

And religions, again & again, have emphasised the need to go beyond the limit of our rational minds.  Christ says "Verily I say unto you, except ye be converted, and become as little children, ye shall not enter into the kingdom of heaven."  And so too have artists & writers.  There is William Blake's "To see a world in a grain of sand; And a heaven in a wild flower; Hold infinity in the palm of your hand; And eternity in an hour" and Elizabeth Barrett Browning's "Earth's crammed with heaven/And every common bush afire with God/But only he who sees, takes off his shoes/The rest sit round it and pluck blackberries."  In the first stanza of Wordsworth's famous poem "Ode: Intimations of immortality", he describes the loss of childhood vision: 

There was a time when meadow, grove, and stream,
The earth, and every common sight,
To me did seem
Apparelled in celestial light,
The glory and the freshness of a dream.
It is not now as it hath been of yore;—
Turn wheresoe'er I may,
By night or day,
The things which I have seen I now can see no more. 

And note too psychologists' comments about this.  Abraham Maslow wrote "The goal of identity (self-actualization ... ) seems to be simultaneously an end-goal in itself, and also a transitional goal, a rite of passage, a step along the path to the transcendence of identity."  And in a new look at Maslow's work, Scott Kaufman - see his paper "Self-actualizing people in the 21st century: Integration with contemporary theory and research on personality and well-being" - has developed a new publically available "Characteristics of self-actualization scale" which it's fascinating to note contains a series of items on self-transcencence.  See too a neuroscientist's take on this in Andrew Neuberg's recent book "Neurotheology".  And Robin Carhart-Harris, probably our central UK psychedelic researcher, talks about how much we see the world through operating models ... lenses, charts that often help us be efficient but also cut us off from freshness, from wonder, from 'the miraculous'.  Blaise Pascal said "Small minds are concerned with the extraordinary, great minds with the ordinary" and Natalie Goldberg underlined this saying "We must remember that everything is ordinary and extraordinary.  It is our minds that either open or close."   

Robin has argued that psychedelics increase our sense of connection - "Psychedelics and connectedness" - and that ego dissolution and a deep realisation of unity are two sides of the same coin ... maybe one is the exit door and the other what one dissolves into.  My own take on it (after eight psilocybin trips during 2019, from a low dose to a very high one ... and also reading the great majority of the recent research) is that our 9 to 5 egos are an often helpful evolutionary development that emerged as our organisms/our minds became more complex.  But our 'egos' are an emergent property, like having an opposable thumb or being able to walk upright ... and they come with costs ... and one of the big costs is that we can get 'shut in', imagining that this little world, this little 'personal house' we live our lives from is the whole universe ... and it clearly isn't.  As Isaac Asimov put it “Your assumptions are your window on the world. Scrub them off every once in a while, or the light won’t come in.” 

Interesting, informative research papers on the various benefits achievable through the use of psychedelics for 'normal subjects' emerge fairly steadily.  Here are a selection:

Gandy, S (2019).  "Psychedelics and potential benefits in 'healthy normals': a review of the literature."  (Available in free full text) We are in the midst of a psychedelic research renaissance. With research examining the efficacy of psychedelics as a treatment for a range of mental health indications still in its early stages, there is an increasing body of research to show that careful use of psychedelics can yield a variety of benefits in “healthy normals” and so lead to “the betterment of well people.” Psychedelics have been found to modulate neuroplasticity, and usage in a supportive setting can result in enduring increases in traits such as well-being, life satisfaction, life meaning, mindfulness, and a variety of measures associated with prosocial behaviors and healthy psychological functioning. The effect of psychedelic experience on measures of personality trait openness and is potential implications is examined, and the potential role of awe as a mediator of the benefits of the psychedelic experience is discussed. Special attention is given to the capacity of psychedelics to increase measures of nature relatedness in an enduring sense, which is being correlated with a broad range of measures of psychological well-being as well as a key predictor of pro-environmental awareness and behavior. The effects of particular classical psychedelic compounds on healthy people are discussed, with special attention given to the mystical-type experiences occasioned by high doses of psychedelics, which appear to be an important mediator of long-term benefits and psychotherapeutic gains. Research looking at the potential benefits of psychedelic microdosing is discussed. Potential future research avenues are explored, focusing on the potential development of psychedelics as agents of ecotherapy.

Elsey, J. W. B. (2017). "Psychedelic drug use in healthy individuals: A review of benefits, costs, and implications for drug policy"  (Available in free full text) The potential of psychedelic drugs in the treatment of mental health problems is increasingly being recognized. However, relatively little thrust has been given to the suggestion that individuals without any mental health problems may benefit from using psychedelic drugs, and that they may have a right to do so. This review considers contemporary research into the use of psychedelic drugs in healthy individuals, including neurobiological and subjective effects. In line with findings suggesting positive effects in the treatment of mental health problems, such research highlights the potential of psychedelic drugs for the enhancement of wellbeing even in healthy individuals. The relatively low risk associated with usage does not appear to align with stringent drug laws that impose heavy penalties for their use. Some policy implications, and suggestions for future research, are considered.

Note recent survey data reports that nearly 10% of the adult US population have taken a hallucinogen at some stage in their lives.  With a US total population of in 2017 of about 328 million (of whom about 24% are in the 0-18 age group), this means around 25 million US adults report having taken some kind of hallucinogen (these figures include substances such as MDMA).  The authors state "Hallucinogen use was assessed using questions regarding past 12 months and lifetime use of Lysergic Acid Diethylamide (LSD), peyote, mescaline, psilocybin, anticholinergics, N,N-Dimethyltryptamine (DMT),2,5-Dimethoxy-4- methylamphetamine (DOM), Dimethoxybromoamphetamine (DOB), Salvia divinorum, dextromethorphan, and phencyclidine."  This seems a pity to me, as "hallucinogen use" as defined in this paper lumps together both the classic psychedelics - LSD, peyote, mescaline, psilocybin and DMT - with a bit of a ragbag of other substances - anticholinergics, DOM, DOB, salvia, dextromethorphan, and phencyclidine.  Recent research - "Anticholinergic drug exposure and the risk of dementia" - comments that anticholinergics are associated with over 10% of new cases of dementia.  Why are we grouping substances with these sorts of actions with classic psychedelics and then thinking the research can clarify how this bundle of different chemical compounds affects people?

Smigielski, L., et al. (2019). "Characterization and prediction of acute and sustained response to psychedelic psilocybin in a mindfulness group retreat." Scientific Reports 9(1): 14914. (Available in free full text) Meditation and psychedelics have played key roles in humankind’s search for self-transcendence and personal change. However, neither their possible synergistic effects, nor related state and trait predictors have been experimentally studied. To elucidate these issues, we administered double-blind the model psychedelic drug psilocybin (315 μg/kg PO) or placebo to meditators (n = 39) during a 5-day mindfulness group retreat. Psilocybin increased meditation depth and incidence of positively experienced self-dissolution along the perception-hallucination continuum, without concomitant anxiety. Openness, optimism, and emotional reappraisal were predictors of the acute response. Compared with placebo, psilocybin enhanced post-intervention mindfulness and produced larger positive changes in psychosocial functioning at a 4-month follow-up, which were corroborated by external ratings, and associated with magnitude of acute self-dissolution experience. Meditation seems to enhance psilocybin’s positive effects while counteracting possible dysphoric responses. These findings highlight the interactions between non-pharmacological and pharmacological factors, and the role of emotion/attention regulation in shaping the experiential quality of psychedelic states, as well as the experience of selflessness as a modulator of behavior and attitudes. A better comprehension of mechanisms underlying most beneficial psychedelic experiences may guide therapeutic interventions across numerous mental conditions in the form of psychedelic-assisted applications.  [Note 315μg/kg is equivalent to about 22mg of psilocybin for a 70kg subject].

Russ, S. L., et al. (2019). "Replication and extension of a model predicting response to psilocybin."  Psychopharmacology. Background Recent research demonstrated the potential of psychedelic drugs as treatment for depression and death-related anxiety and as an enhancement for well-being. While generally positive, responses to psychedelic drugs can vary according to traits, setting, and mental state (set) before and during ingestion. Most earlier models explain minimal response variation, primarily related to dosage and trust, but a recent study found that states of surrender and preoccupation at the time of ingestion explained substantial variance in mystical and adverse psilocybin experiences.  Objectives The current study sought to replicate the previous model, extend the model with additional predictors, and examine the role of mystical experience on positive change.  Method A hierarchical regression model was created with crowdsourced retrospective data from 183 individuals who had self-administered psilocybin in the past year. Scales explored mental states before, during, and after psilocybin ingestion, relying on open-ended memory prompts at each juncture to trigger recollections. Controlled drug administration was not employed.  Results This study replicated the previous model, finding a state of surrender before ingestion a key predictor of optimal experience and preoccupation a key predictor of adverse experience. Additional predictors added to the explanatory power for optimal and adverse experience. The model supported the importance of mystical experiences to long-term change.  Conclusion Mental states of surrender or preoccupation at the time of ingestion explain variance in mystical or adverse psilocybin experiences, and mystical experiences relate to long-term positive change. The capacity to recognize this optimal preparatory mental state may benefit therapeutic use of psilocybin in clinical settings.

Kettner, H., et al. (2019). "From egoism to ecoism: psychedelics increase nature relatedness in a state-mediated and context-dependent manner." International Journal of Environmental Research and Public Health 16(24): 5147. (Available in free full text) (1) Background: There appears to be a growing disconnection between humans and their natural environments which has been linked to poor mental health and ecological destruction. Previous research suggests that individual levels of nature relatedness can be increased through the use of classical psychedelic compounds, although a causal link between psychedelic use and nature relatedness has not yet been established. (2) Methods: Using correlations and generalized linear mixed regression modelling, we investigated the association between psychedelic use and nature relatedness in a prospective online study. Individuals planning to use a psychedelic received questionnaires 2 weeks before (N = 654), plus one day, 2 weeks, 4 weeks, and 2 years after a psychedelic experience. (3) Results: The frequency of lifetime psychedelic use was positively correlated with nature relatedness at baseline. Nature relatedness was significantly increased 2 weeks, 4 weeks and 2 years after the psychedelic experience. This increase was positively correlated with concomitant increases in psychological well-being and was dependent on the extent of ego-dissolution and the perceived influence of natural surroundings during the acute psychedelic state. (4) Conclusions: The here presented evidence for a context- and state-dependent causal effect of psychedelic use on nature relatedness bears relevance for psychedelic treatment models in mental health and, in the face of the current ecological crisis, planetary health.

Griffiths, R. R., et al. (2019). "Survey of subjective "God encounter experiences": Comparisons among naturally occurring experiences and those occasioned by the classic psychedelics psilocybin, LSD, ayahuasca, or DMT."  PLoS ONE 14(4): e0214377. (Available in free full text) Naturally occurring and psychedelic drug–occasioned experiences interpreted as personal encounters with God are well described but have not been systematically compared. In this study, five groups of individuals participated in an online survey with detailed questions characterizing the subjective phenomena, interpretation, and persisting changes attributed to their single most memorable God encounter experience (n = 809 Non-Drug, 1184 psilocybin, 1251 lysergic acid diethylamide (LSD), 435 ayahuasca, and 606 N,N-dimethyltryptamine (DMT)). Analyses of differences in experiences were adjusted statistically for demographic differences between groups. The Non-Drug Group was most likely to choose "God" as the best descriptor of that which was encountered while the psychedelic groups were most likely to choose "Ultimate Reality." Although there were some other differences between non-drug and the combined psychedelic group, as well as between the four psychedelic groups, the similarities among these groups were most striking. Most participants reported vivid memories of the encounter experience, which frequently involved communication with something having the attributes of being conscious, benevolent, intelligent, sacred, eternal, and all-knowing. The encounter experience fulfilled a priori criteria for being a complete mystical experience in approximately half of the participants. More than two-thirds of those who identified as atheist before the experience no longer identified as atheist afterwards. These experiences were rated as among the most personally meaningful and spiritually significant lifetime experiences, with moderate to strong persisting positive changes in life satisfaction, purpose, and meaning attributed to these experiences. Among the four groups of psychedelic users, the psilocybin and LSD groups were most similar and the ayahuasca group tended to have the highest rates of endorsing positive features and enduring consequences of the experience. Future exploration of predisposing factors and phenomenological and neural correlates of such experiences may provide new insights into religious and spiritual beliefs that have been integral to shaping human culture since time immemorial.

Diebels, K. J. and M. R. Leary (2019). "The psychological implications of believing that everything is one." The Journal of Positive Psychology 14(4): 463-473. ABSTRACT A variety of philosophical, religious, spiritual, and scientific perspectives converge on the notion that everything that exists is part of some fundamental entity, substance, or process. People differ in the degree to which they believe that everything is one, but we know little about the psychological or social implications of holding this belief. In two studies, believing in oneness was associated with having an identity that includes distal people and the natural world, feeling connected to humanity and nature, and having values that focus on other people’s welfare. However, the belief was not associated with a lower focus on oneself or one’s concerns. Participants who believed in oneness tended to view themselves as spiritual but not necessarily religious, and reported experiences in which they directly perceived everything as one. The belief in oneness is a meaningful existential belief that has numerous implications for people’s self-views, experiences, values, relationships, and behavior.

Jungaberle, H., et al. (2018). "Positive psychology in the investigation of psychedelics and entactogens: A critical review"  Neuropharmacology 142: 179-199.  Rationale We reviewed the concepts and empirical findings in studies with psychedelics and entactogens related to positive psychology – the study of healthy human functioning, well-being and eudaemonia. It is an unresolved question how beneficial effects of psychedelics and entactogens are related to the potential risks of these substances – particularly in non-clinical settings. Methods We searched in PubMed, PsychINFO and the Cochrane Library for controlled clinical and epidemiological studies which applied concepts from positive psychology. We included N = 77 eligible studies with 9876 participants published before November 1st, 2017: (1) quantitative studies (N = 54), (2) preliminary or exploratory studies and reviews not including meta-analyses (N = 17), and (3) studies evidencing primarily negative results (N = 6). Results Positive psychology concepts have been applied for measuring effects of clinical trials, recreational and ceremonial use of psychedelics and entactogens. Psychedelics and entactogens were shown to produce acute and long-term effects on mood, well-being, prosocial behaviours, empathy, cognitive flexibility, creativity, personality factors like openness, value orientations, nature-relatedness, spirituality, self-transcendence and mindfulness-related capabilities. Conclusions There is preliminary evidence for beneficial effects of psychedelics and entactogens on measures of positive psychology in clinical and healthy populations, however their sustainability remains largely unresolved. The reported results must be considered preliminary due to methodological restrictions. Since longitudinal data on both positive and adverse effects of psychedelics are lacking, more rigorous and standardized measures from positive psychology should be applied in less biased populations with prospective longitudinal designs to carefully assess the benefit-risk-ratio. This article is part of the Special Issue entitled ‘Psychedelics: New Doors, Altered Perceptions’.

Barrett, F. S. and R. R. Griffiths (2018). "Classic hallucinogens and mystical experiences: Phenomenology and neural correlates"  Curr Top Behav Neurosci 36: 393-430.  This chapter begins with a brief review of descriptions and definitions of mystical-type experiences and the historical connection between classic hallucinogens and mystical experiences. The chapter then explores the empirical literature on experiences with classic hallucinogens in which claims about mystical or religious experiences have been made. A psychometrically validated questionnaire is described for the reliable measurement of mystical-type experiences occasioned by classic hallucinogens. Controlled laboratory studies show that under double-blind conditions that provide significant controls for expectancy bias, psilocybin can occasion complete mystical experiences in the majority of people studied. These effects are dose-dependent, specific to psilocybin compared to placebo or a psychoactive control substance, and have enduring impact on the moods, attitudes, and behaviors of participants as assessed by self-report of participants and ratings by community observers. Other studies suggest that enduring personal meaning in healthy volunteers and therapeutic outcomes in patients, including reduction and cessation of substance abuse behaviors and reduction of anxiety and depression in patients with a life-threatening cancer diagnosis, are related to the occurrence of mystical experiences during drug sessions. The final sections of the chapter draw parallels in human neuroscience research between the neural bases of experiences with classic hallucinogens and the neural bases of meditative practices for which claims of mystical-type experience are sometimes made. From these parallels, a functional neural model of mystical experience is proposed, based on changes in the default mode network of the brain that have been observed after the administration of classic hallucinogens and during meditation practices for which mystical-type claims have been made.

Griffiths, R. R., et al. (2018). "Psilocybin-occasioned mystical-type experience in combination with meditation and other spiritual practices produces enduring positive changes in psychological functioning and in trait measures of prosocial attitudes and behaviors"  J Psychopharmacol 32(1): 49-69.  (Available in free full text) Psilocybin can occasion mystical-type experiences with participant-attributed increases in well-being. However, little research has examined enduring changes in traits. This study administered psilocybin to participants who undertook a program of meditation/spiritual practices. Healthy participants were randomized to three groups (25 each): (1) very low-dose (1 mg/70 kg on sessions 1 and 2) with moderate-level ("standard") support for spiritual-practice (LD-SS); (2) high-dose (20 and 30 mg/70 kg on sessions 1 and 2, respectively) with standard support (HD-SS); and (3) high-dose (20 and 30 mg/70kg on sessions 1 and 2, respectively) with high support for spiritual practice (HD-HS). Psilocybin was administered double-blind and instructions to participants/staff minimized expectancy confounds. Psilocybin was administered 1 and 2 months after spiritual-practice initiation. Outcomes at 6 months included rates of spiritual practice and persisting effects of psilocybin. Compared with low-dose, high-dose psilocybin produced greater acute and persisting effects. At 6 months, compared with LD-SS, both high-dose groups showed large significant positive changes on longitudinal measures of interpersonal closeness, gratitude, life meaning/purpose, forgiveness, death transcendence, daily spiritual experiences, religious faith and coping, and community observer ratings. Determinants of enduring effects were psilocybin-occasioned mystical-type experience and rates of meditation/spiritual practices. Psilocybin can occasion enduring trait-level increases in prosocial attitudes/behaviors and in healthy psychological functioning.

Aixalá, M., et al. (2019). "Patterns of use, desired effects, and mental health status of a sample of natural psychoactive drug users." Drugs: Education, Prevention and Policy: 1-8. Abstract In recent years, the use of natural psychoactive drugs (NPDs) has grown rapidly. They are classified as new psychoactive substances (NPSs), despite the reality that they have been used for centuries. We are lacking information regarding patterns of use or characteristics of users, but some evidence suggests that NPDs substantially differ from NPSs in terms of both their safety profile and patterns of use. The aim of this study was to investigate patterns of use and user characteristics by collecting data from a sample of NPD users. We designed an online questionnaire that was shared through social media. A sample of 564 NPD users was recruited from 52 different countries, with the United States being the most common (19%), followed by Spain (14.9%). The typical user in our sample is a well-educated adult individual who uses NPDs sporadically. The most used substances were Psilocybe mushrooms (88.5%) and ayahuasca (51%). Users reported that the use of NPDs positively influenced their lives, and they showed a good mental health status. Stakeholders should consider these results particularly when deciding on legal classifications for these substances, as the study findings suggest that NPDs should not be in the same class as NPSs.

Hendricks, P. S., et al. (2018). "The relationships of classic psychedelic use with criminal behavior in the United States adult population"  Journal of Psychopharmacology 32(1): 37-48.  Criminal behavior exacts a large toll on society and is resistant to intervention. Some evidence suggests classic psychedelics may inhibit criminal behavior, but the extent of these effects has not been comprehensively explored. In this study, we tested the relationships of classic psychedelic use and psilocybin use per se with criminal behavior among over 480,000 United States adult respondents pooled from the last 13 available years of the National Survey on Drug Use and Health (2002 through 2014) while controlling for numerous covariates. Lifetime classic psychedelic use was associated with a reduced odds of past year larceny/theft (aOR = 0.73 (0.65–0.83)), past year assault (aOR = 0.88 (0.80–0.97)), past year arrest for a property crime (aOR = 0.78 (0.65–0.95)), and past year arrest for a violent crime (aOR = 0.82 (0.70–0.97)). In contrast, lifetime illicit use of other drugs was, by and large, associated with an increased odds of these outcomes. Lifetime classic psychedelic use, like lifetime illicit use of almost all other substances, was associated with an increased odds of past year drug distribution. Results were consistent with a protective effect of psilocybin for antisocial criminal behavior. These findings contribute to a compelling rationale for the initiation of clinical research with classic psychedelics, including psilocybin, in forensic settings.

Millière, R., et al. (2018). "Psychedelics, meditation, and self-consciousness"  Frontiers in Psychology 9: 1475-1475.  (Available in free full text) In recent years, the scientific study of meditation and psychedelic drugs has seen remarkable developments. The increased focus on meditation in cognitive neuroscience has led to a cross-cultural classification of standard meditation styles validated by functional and structural neuroanatomical data. Meanwhile, the renaissance of psychedelic research has shed light on the neurophysiology of altered states of consciousness induced by classical psychedelics, such as psilocybin and LSD, whose effects are mainly mediated by agonism of serotonin receptors. Few attempts have been made at bridging these two domains of inquiry, despite intriguing evidence of overlap between the phenomenology and neurophysiology of meditation practice and psychedelic states. In particular, many contemplative traditions explicitly aim at dissolving the sense of self by eliciting altered states of consciousness through meditation, while classical psychedelics are known to produce significant disruptions of self-consciousness, a phenomenon known as drug-induced ego dissolution. In this article, we discuss available evidence regarding convergences and differences between phenomenological and neurophysiological data on meditation practice and psychedelic drug-induced states, with a particular emphasis on alterations of self-experience. While both meditation and psychedelics may disrupt self-consciousness and underlying neural processes, we emphasize that neither meditation nor psychedelic states can be conceived as simple, uniform categories. Moreover, we suggest that there are important phenomenological differences even between conscious states described as experiences of self-loss. As a result, we propose that self-consciousness may be best construed as a multidimensional construct, and that "self-loss," far from being an unequivocal phenomenon, can take several forms. Indeed, various aspects of self-consciousness, including narrative aspects linked to autobiographical memory, self-related thoughts and mental time travel, and embodied aspects rooted in multisensory processes, may be differently affected by psychedelics and meditation practices. Finally, we consider long-term outcomes of experiences of self-loss induced by meditation and psychedelics on individual traits and prosocial behavior. We call for caution regarding the problematic conflation of temporary states of self-loss with "selflessness" as a behavioral or social trait, although there is preliminary evidence that correlations between short-term experiences of self-loss and long-term trait alterations may exist.

Johansen, P.-Ø. and T. S. Krebs (2015). "Psychedelics not linked to mental health problems or suicidal behavior: A population study"  Journal of Psychopharmacology 29(3): 270-279.  A recent large population study of 130,000 adults in the United States failed to find evidence for a link between psychedelic use (lysergic acid diethylamide, psilocybin or mescaline) and mental health problems. Using a new data set consisting of 135,095 randomly selected United States adults, including 19,299 psychedelic users, we examine the associations between psychedelic use and mental health. After adjusting for sociodemographics, other drug use and childhood depression, we found no significant associations between lifetime use of psychedelics and increased likelihood of past year serious psychological distress, mental health treatment, suicidal thoughts, suicidal plans and suicide attempt, depression and anxiety. We failed to find evidence that psychedelic use is an independent risk factor for mental health problems. Psychedelics are not known to harm the brain or other body organs or to cause addiction or compulsive use; serious adverse events involving psychedelics are extremely rare. Overall, it is difficult to see how prohibition of psychedelics can be justified as a public health measure.

Hendricks, P. S., et al. (2015). "Classic psychedelic use is associated with reduced psychological distress and suicidality in the United States adult population"  Journal of Psychopharmacology.  Mental health problems are endemic across the globe, and suicide, a strong corollary of poor mental health, is a leading cause of death. Classic psychedelic use may occasion lasting improvements in mental health, but the effects of classic psychedelic use on suicidality are unknown. We evaluated the relationships of classic psychedelic use with psychological distress and suicidality among over 190,000 USA adult respondents pooled from the last five available years of the National Survey on Drug Use and Health (2008–2012) while controlling for a range of covariates. Lifetime classic psychedelic use was associated with a significantly reduced odds of past month psychological distress (weighted odds ratio (OR)=0.81 (0.72–0.91)), past year suicidal thinking (weighted OR=0.86 (0.78–0.94)), past year suicidal planning (weighted OR=0.71 (0.54–0.94)), and past year suicide attempt (weighted OR=0.64 (0.46–0.89)), whereas lifetime illicit use of other drugs was largely associated with an increased likelihood of these outcomes. These findings indicate that classic psychedelics may hold promise in the prevention of suicide, supporting the view that classic psychedelics’ most highly restricted legal status should be reconsidered to facilitate scientific study, and suggesting that more extensive clinical research with classic psychedelics is warranted.

Moro, L., et al. (2011). "Voice of the psychonauts: coping, life purpose, and spirituality in psychedelic drug users"  Psychoactive drug use shows great diversity, but due to a disproportionate focus on problematic drug use, predominant nonproblematic drug use remains an understudied phenomenon. Historic and anecdotal evidence shows that natural sources of "psychedelic" drugs (e.g., mescaline and psilocybin) have been used in religious and spiritual settings for centuries, as well as for psychological self-enhancement purposes. Our study assessed a total of 667 psychedelic drug users, other drug users, and drug nonusers by online questionnaires. Coping, life purpose, and spirituality were measured with the Psychological Immune Competence Inventory, the Purpose in Life test, and the Intrinsic Spirituality Scale, respectively. Results indicate that the use of psychedelic drugs with a purpose to enhance self-knowledge is less associated with problems, and correlates positively with coping and spirituality. Albeit the meaning of "spirituality" may be ambiguous, it seems that a spiritually-inclined attitude in drug use may act as a protective factor against drug-related problems. The autognostic use of psychedelic drugs may be thus hypothesized as a "training situation" that promotes self-enhancement by rehearsing personal coping strategies and by gaining self-knowledge. However, to assess the actual efficiency and the speculated long-term benefits of these deliberately provoked exceptional experiences, further qualitative investigations are needed.

These are the two quotations from John Stuart Mill (sometimes known as "the most influential English-speaking philosopher of the nineteenth century") given by Professor David Nutt on the final slide of his Edinburgh Science Festival lecture "Why Scotland should lead the neuroscientific enlightenment":  They seem an appropriate ending to this post!      

"In a freedom-loving society no conduct by rational adults should be made criminal unless it is harmful to others." 

"In this age, the mere example of non-conformity, the mere refusal to bend the knee to custom, is itself a service."