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In our literature study we came across the following studies of note. Browse the meta, review, commentary articles for an overview. Check out the individual studies for specific experiments and observations.
Phenomenology, Structure, and Dynamic of Psychedelic States
2016 | Preller, K. H., Vollenweider, F. X.
This academic book chapter (2016) explores the phenomenology, structure, and dynamic of altered states of consciousness (ASC) produced by classic serotonergic hallucinogens or psychedelics.
Psychedelics and hypnosis: Commonalities and therapeutic implications
2021 | Lemercier, C. E., Terhune, D. B.
The review (2018) examines the similarities between psychedelics and hypnosis with respect to their neurophenomenological features and therapeutic applications and highlights the potential for harnessing the power of suggestion to influence the phenomenological response to psychedelics in the context of therapy.
Key interindividual determinants in MDMA pharmacodynamics
2018 | Farré, M., Muga, R., Papaseit, E., Pérez-Mañá, C., Torrens, M.
This review (2018) examines the main interindividual determinants in MDMA pharmacodynamics and highlights the influence of factors such as gender-sex (more pronounced in women because of weight difference), race-ethnicity, and genetic traits.
Future Directions for Clinical Psychedelic Research: The Relaxed Symptom Network
2021 | Laukkonen, R., Lewis-Healey, E., van Elk, M.
This preprint (2021) extends the methodological framework for investigating the efficacy of psychedelic-assisted therapy by reconceptualizing mental health disorders as an emergent property of psychological, biological, and societal symptom networks which reinforce self-sustained patterns of psychopathology. It is hypothesized that psychedelic-assisted psychotherapy can make people more resilient against depression by weakening the network connections between symptoms and disrupting negative feedback of maladaptive patterns.
Reflections on the Concord Prison Project and the follow-up study
1998 | Metzner, R.
In this commentary (1998), Ralph Metzner reflects on the erroneous conclusions drawn by him and Timothy Leary from the Concord Prison experiment which had falsely reported lowered the rate of recidivism amongst inmates who had undertaken a psychedelic intervention, despite evidence that most prisoners actually returned for parole violations related to committing new crimes. Metzner concludes that although psychedelics can bring about profound experiences of insight and personality change, criminal behavior patterns take a much more concerted system of rehabilitation and community support to change.
Predicting Reactions to Psychedelic Drugs: A Systematic Review of States and Traits Related to Acute Drug Effects
2021 | Aday, J. S., Bloesch, E. K., Davis, A. K., Davoli, C. C., Mitzkovitz, C. M.
This review (14 studies) found that traits of absorption, openness, acceptance, and surrender correlated with more positive and mystical (MEQ30) experiences. Gender didn't predict drug effects, but possible biomarkers are serotonin receptor binding potential, executive network node diversity, and right anterior cingulate cortex volume.
Psychedelics use predicts more positive emotional reactivity and greater self-awareness: the mediating role of ego dissolution and mystical experiences
2021| Bielecki, M., Bola, M., Hobot, J., Orłowski, P., Ruban, A., Szczypiński, J.
This cross-sectional preprint survey study (n=2516) investigated how the frequency of using psychedelics in naturalistic settings and mystical aspects of the induced experiences are related to psychological functioning in the domains of emotional reactivity and self-consciousness. They found that mystical aspects of psychedelic experiences mediated positive emotional reactivity, weaker outward-focused aspects of self, and an adaptive pattern of features constituting internally-focused self among the respondents.
On Revelations and Revolutions: Drinking Ayahuasca Among Palestinians Under Israeli Occupation
2021| Karkabi, N., Roseman, L.
This qualitative case study (n=3) investigates the sociopharmacology of ayahuasca within the context of ritual ceremonies between Palestinians and Israelis and found that it occasioned revelatory events that confronted the participants with the oppressive nature of their surrounding political structure. These revelatory experiences led the participant to develop a universalist counterhegemonic worldview, which motivated them to restructure the ritual space of ayahuasca use to be more inclusive of Palestinians and their culture.
Do Psychedelics Change Beliefs?
2021| Corlett, P. R., Hutchinson, B., Leptourgos, P., McGovern, H.
This theory-building preprint (2021) examines psychedelics facilitate lasting changes in people's beliefs and calls for better-controlled trials that assess baseline beliefs and expectations prior to randomizing individuals to psychedelic interventions to assay the causal role of mystical experiences in the apparent long-term effects of psychedelics.
Cancer Healthcare Workers' Perceptions toward Psychedelic-Assisted Therapy: A Preliminary Investigation
2021| Akroyd, A., Evans, W. J., Muthukumaraswamy, S., Reynolds, L. M, Stack, A., Sundram, F.
This qualitative interview study (n=12) examined the perspectives and attitudes of cancer healthcare workers towards psychedelic-assisted therapy. In general, they were open to the concept, viewed it as an innovative approach, and acknowledged their responsibility towards alleviating suffering in advanced cancer patients. However, this view was also met with caution and highlights the need for further research to ensure efficacy and safety.
Moral Psychopharmacology Needs Moral Inquiry: The Case of Psychedelics
2021| Dyck, E., Langlitz, N., Repantis, D., Scheidegger, M.
This opinion paper (2021) examines the effects of psychedelics on moral flexibility and argues that the context sensitivity of these substances entails that randomized placebo-controlled trials are insufficient for appreciating the full range of their possible effects. In order to understand its effects on moral behavior, the authors advocate a complementary approach of culture-controlled trials that investigate this moral psychopharmacology under different social and cultural circumstances with the help of anthropological, sociological, and philosophical observers, in order to determine what constitutes a good use of psychedelics beyond clinical trials.
Turn on, Tune in, and Drop out: Predictors of Attrition in a Prospective Observational Cohort Study on Psychedelic Use
2021| Carhart-Harris, R. L., Haijen, E. C. H. M., Hübner, S., Kaelen, M., Kettner, H.
This post-hoc survey study (n=654) sought to identify factors accounting for the high attrition rates in a prospective study on naturalistic psychedelic use and found that the strongest predictors for participant dropping out were among demographic variables including age, educational levels, and personality traits, but unrelated to psychedelic-specific factors such as challenging experiences or prior dispositions towards psychedelics. These results partially address concerns over sampling biases results due to high drop-out rates and conclude that future psychedelic research can improve participation through conventional incentives, such as remuneration, gamification, or by forming web-based participant communities.
A Nationwide Study Comparing Mental Health Professionals' Willingness to Try Hallucinogenic Drugs in Basic Research or Clinical Practice
2021| Ben-Sheetrit, J., Lev-Ran, S., Madjar, N., Shoval, G., Weizman, A.
This survey study (n=347) examined Israeli mental health professionals' attitudes toward recreational drug users and willingness to use five hallucinogens (LSD, MDMA, ketamine, cannabis, psilocybin) in research or clinical practice. Compared to nurses and paramedics, psychiatrists were more familiar with the potential therapeutic role of psychedelics and had a higher willingness to conduct research or use such substances for clinical purposes. However, psychiatrists were also the most susceptible to personal bias, as evidenced by cases wherein negative attitudes toward recreational users impeded their support for psychedelic within the context of clinical treatments or research.
Psychedelic drug use and schizotypy in young adults
2021| Åberg, A., Acar, K., Almeida, R., Atlas, L., Garzón, B., Ingvar, M., Lebedev, A. V., Louzolo, A., Lövdén, M., Martinsson, S., Olsson, A., Pärnamets, P., Petrovic, P., Råback, J.
This observational survey (n=1032) and experimental (n=39) study investigated the relationship between psychedelic drug use and schizotypal behavior and personality trait. Results indicate that psychedelics do not pose serious risks for developing psychotic symptoms in healthy young adults, in fact, psychedelic drug exposure was associated with better evidence integration, less bias against disconfirmatory evidence, and more flexible aversive learning, compared to psychos-like behaviors that were more commonly associated with psychostimulant use.
Effects of ayahuasca on personality: results of two randomized, placebo-controlled trials in healthy volunteers
2021| Bouso, J. C., Crevelin, E. J., De Oliveira Silveira, G., Dos Santos, R. G., Hallak, J. E., Osório, F. L., Queiroz, M. E. C., Rocha, J. M., Rossi, G. N., Yonamine, M.
This analysis of data from two double-blind, placebo-controlled studies (n=30) found inconsistent effects of ayahuasca on personality traits. Specifically, increases in Openness that were found in studies with LSD and psilocybin were only found in one arm of one study.
Using Psychedelics With Therapeutic Intent Is Associated With Lower Shame and Complex Trauma Symptoms in Adults With Histories of Child Maltreatment
2021| Healy, C. J., Lee, K. A.
This survey study (n=166) investigates whether psychedelic use moderates the relationships between child maltreatment, self-concept, social cognition, and posttraumatic stress symptoms. Results indicate that using psychedelic drugs with therapeutic intent is associated with lower levels of complex posttraumatic stress symptoms and internalized shame in individuals with histories of child maltreatment.
Working with Weirdness: A Response to “Moving Past Mysticism in Psychedelic Science”
2021| Breeksema, J. J., van Elk, M.
In this opposing viewpoint to 'Moving Past Mysticism', an article which argued that 'mystical' constructs are overly laden with beliefs and do not suffice objective measurement, it is argued that 'mystical experiences' have a rich history of scientific investigation as the authors lay out a brief summary of their underlying constructs and empiric validation. They argue that the sole reliance on brain-based explanations is essentially a type of 'neuroenchantment' that ignores the transformative impact of subjective experiences on people’s lives, behavior, and values. The authors state that research should remain open to all varieties of the psychedelic experience, including weird and extraordinary states that do not conform to western culture and its expectations.
Recreational 3,4-methylenedioxy-N-methylamphetamine (MDMA) or ‘ecstasy’ and self-focused compassion: Preliminary steps in the development of a therapeutic psychopharmacology of contemplative practices
2015| Curran, H. V., Das, R. K., Falconer, C. J., Freeman, T. P., Gilbert, P., Kamboj, S. K., Kilford, E. J., Lawn, W., Minchin, S., Moss, A.
This open-label, observational, within-subjects study (n=20) investigated the effects of MDMA on compassionate attitudes before and after recreational use, compared to a sober state, and found that it reduced self-criticism and increased self-compassion in exposure to compassionate imagery.
Use of Benefit Enhancement Strategies among 5-Methoxy-N,N-Dimethyltryptamine (5-MeO-DMT) Users: Associations with Mystical, Challenging, and Enduring Effects
2020| Davis, A. K., Lancelotta, R.
This observational survey study (n = 515) examines the prevalence of benefit enhancement (BE) strategies using secondary data from a survey of 5-MeO-DMT users and its associations with "mystical", challenging, and enduring effects. It concluded that the BE strategies were common in use and BE strategies were linked to increases in positive mystical-type and enduring effects.
Naturalistic Entheogenics: Précis of Philosophy of Psychedelics
2021| Letheby, C.
This preprint (2021) summarizes the main ideas of the 'Philosophy of Psychedelics' book by the author Chris Letheby, wherein he examines whether the efficacy of psychedelic therapies is contingent upon the induction of non-naturalistic metaphysical beliefs related to mystical experiences. He essentially argues that psychedelic therapy hinges on a genuinely psychological mechanism that involves the psychedelic experience itself, and works mainly by disrupting and revising mental representations of the self.
Exploring the Use of Psilocybin Therapy for Existential Distress: A Qualitative Study of Palliative Care Provider Perceptions
2021| Acquaviva, K. D., LeBaron, V. T., Mayer, C. E.
This qualitative interview study (n=5) examines the attitudes of palliative care workers towards the use of psilocybin therapy for death anxiety and identified common themes concerning the perceived barriers of treating existential distress and their uncertainty about the risks and benefits of psilocybin.
Psychedelic use and intimate partner violence
2018| Bird, B. M., Lafrance, A., Thiessen, M. S., Walsh, Z.
This survey (n=1266) examines the correlation between lifetime psychedelic use of LSD and/or psilocybin and intimate partner violence in a community sample of men and women using an online questionnaire. Contrary to the generally held belief, the study found that men using LSD and/or psilocybin had reduced odds of physical violence against their current partner and that also reported better emotion regulation as compared to males with no history of psychedelic use. The study underlined the potential of emotion regulation in this dynamic.
Mental health of a self-selected sample of psychedelic users and self-medication practices with psychedelics
2018| Kuypers, K. P. C., Mason, N. L.
The observational survey study (n=1,967) investigated the frequency and efficacy of self-medication practices amongst psychedelic users and found that the prevalence of lifetime psychopathologies amongst psychedelic users was higher than in the general population. Although psychedelics were seldom used for self-medication, those who did use psychedelics in this manner reported it to be more effective than the current lines of treatment for mental illness.
Greater empathy in MDMA users
2019| Carlyle, M., Fawaz, L., Kosmider, S., Marsh, B., Morgan, C. J. A., Stevens, T.
This observational cohort study (n=67) compared the long-term effects of repeated MDMA use on empathy and the experience of social pain between MDMA, alcohol, and poly-drug users. MDMA users exhibited greater cognitive and emotional empathy compared with non-MDMA poly-drug users.
LSD, madness and healing: Mystical experiences as possible link between psychosis model and therapy model
2021| Falchi, M., Feilding, A., Palhano-Fontes, F., Ribeiro, S., Tófoli, L.F., Wießner, I.
This randomized, double-blind, placebo-controlled, crossover study (n=24) investigated the subjective effects of LSD and found significant overlap in the phenomenology of psychotic, mystical, and ego-dissolving experiences. The authors highlight the importance of meaning attribution to psychotic experiences in explaining how these different constructs converge in mystical experiences.
High dose psilocybin is associated with positive subjective effects in healthy volunteers
2018| Brown, R., Cooper, K., Cozzi, N. V., Gassman, M. C., Henriquez, K. M., Hetzel, S. J., Hutson, P. R., Muller, D., Nicholas, C. R., Thomas, C.
This open-label study (n=12) investigates the positive subjective effects in response to escalating doses of oral psilocybin (21, 31.5, 42 mg/70k) in healthy participants and found that both the highest and the low doses induced equally strong mystical experiences and persisting positive effects that lasted 30 days after ingestion.
Lifetime experience with (classic) psychedelics predicts pro-environmental behavior through an increase in nature relatedness
2017| Forstmann, M., Sagioglou, C.
This survey study (n=1487) probed the association between experience with classic psychedelic substances and pro-environmental behavior using structural equation modeling. The conclusion found that the lifetime experience with psychedelics may indeed be a factor in people’s pro-environmental behavior by altering their self-construal in terms of an incorporation of the natural world, regardless of core personality traits or general proclivity to use mind-altering substances. This indicates the potentially positive effects on a societal level and also supports the beneficial effects of psychedelic use on mental health.
Survey of subjective “God encounter experiences”: Comparisons among naturally occurring experiences and those occasioned by the classic psychedelics psilocybin, LSD, ayahuasca, or DMT
2019| Davis, A. K., Griffiths, R. R., Hurwitz, E., Jesse, R., Johnson, M. W.
This survey study (n=4258) compares natural (non-drug) and psychedelic (LSD, psilocybin, ayahuasca, DMT) reported "God encounter experiences" and finds very similar descriptions. For half of the participants the experience qualified as a full mystical experience, more than 67% of participants who identified as atheists didn't do so after the experience (e.g. became agnostic).
Effect of psilocybin on empathy and moral decision-making
2017| Dziobek, I., Kometer, M., Pokorny, T., Preller, K. H., Vollenweider, F. X.
This placebo-controlled study (n=56) investigated the acute effect of psilocybin (15mg/70kg) on empathy and moral decision-making in healthy human subjects. The results found the first such evidence that psilocybin has distinct effects on social cognition by enhancing emotional empathy but not moral behavior. It also supports previous findings, indicating that psilocybin may promote emotional empathy presumably through activation of serotonin 2A/1A receptors, showing that focusing on serotonin 2A/1A receptors has the potential to treat dysfunctional social cognition.
Role of the 5-HT2A receptor in acute effects of LSD on empathy and circulating oxytocin
2021| Avedisian, I., Eckert, A., Holze, F., Liechti, M. E., Varghese, N.
This double-blind placebo-controlled crossover study (n=16) finds that LSD (200 µg) improves emotional empathy, and moderately increases plasma oxytocin levels. Ketanserin reduced the elevation of oxytocin but not the increase in emotional empathy (arguing that the latter isn't dependent on the 5HT-2a receptor pathway).
Psychedelics alter metaphysical beliefs
2021| Carhart-Harris, R. L., Kettner, H., Letheby, C., Rosas, F. E., Roseman, L., Timmermann, C.
This pre-print study of prospective survey data (n=866) finds that psychedelics indeed alter metaphysical beliefs and shift them towards panpsychism and fatalism (away from physicalist/materialist). The level of impressionability, and the level of emotional synchrony mediated these effects.
Ayahuasca and Public Health: Health Status, Psychosocial Well-Being, Lifestyle, and Coping Strategies in a Large Sample of Ritual Ayahuasca Users
2018| Alcázar-Córcoles, M. A., Bouso, J. C., Dos Santos, R. G., Gomariz, A., Hallak, J. E., Jiménez-Garrido, D. F., Kohek, M., Massaguer, T., Ona, G.
This study (n=380) focuses on psycho-social well-being, lifestyle, and coping strategies in a large sample of long-term ayahuasca users. The participants in this study associated long-term ayahuasca use with a higher positive perception of health or with a healthy lifestyle, among others. The study offers insight into the long-term effects of ayahuasca on public health and proposes incorporating a "communitarian approach" into society to benefit public health to ensure a respectful and controlled use of hallucinogenic/psychedelic drugs.
Psychedelic perceptions: mental health service user attitudes to psilocybin therapy
2021| Cleary, S., Corrigan, K., Haran, M., Kelly, J. R., Kelly, Y., Ledden, K., McCandliss, C., McManus, R., O’Keane, V., Rush, G., Trant, R.
This survey study (n=99) examined the attitude of mental health service users towards psilocybin therapy in Ireland and found that most respondents were supportive of research into psilocybin therapy, while support for therapy itself came mostly from respondents with non-religious beliefs and prior recreational experience with psychedelics.
Trait Openness and serotonin 2A receptors in healthy volunteers: A positron emission tomography study
2018| Burmester, D., Fisher, P. M., Frokjaer, V. G., Knudsen, G. M., Kristiansen, S., Madsen, M. K., Stenbæk, D. S.
This positron emission tomography (PET) study (n=159) found no relationship between the availability of 5-HT 2A receptors and variation in trait Openness in healthy individuals, even though psychedelic compounds such as psilocybin have been shown to increase trait openness and stimulate the 5HT2A receptor pathway.
‘Never drop without your significant other, cause that way lies ruin’: The boundary work of couples who use MDMA together
2019| Anderson, K., Boden, Z., Reavey, P.
This qualitative interview and diary study (n=14) investigated the context in which romantic couples use MDMA and found that it occasioned shared experiences which could modulate and enhance existing feelings of closeness in the process of being subsumed into things that couples enjoyed doing together, to the effect that it refreshed and revitalized their relationship.
Embracing Neurodiversity in Psychedelic Science: A Mixed-Methods Inquiry into the MDMA Experiences of Autistic Adults
2019| Danforth, A. L.
This retrospective survey (n=100) and qualitative interview (n=24) study examined the MDMA experiences of autistic adults and identified that many of them viewed MDMA as a transformative healing catalyst for helping their anxieties of navigating through neurotypical social norms, while none of them expressed the desire for being neurotypical or reported being "cured" from autism.
Visitors of the Dutch drug checking services: Profile and drug use experience
2021| Benschop, A., Koning, R., Noijen, J., Wijffels, C.
This survey study (n=1530) examined the demographic profiles of people who made use of drug checking services in the Netherlands in 2018 and found that most participants who acquired this service had longstanding experience and a higher lifetime prevalence of using ecstasy/MDMA than the average Dutch citizen.
Cross-sectional associations between lifetime use of psychedelic drugs and psychometric measures during the COVID-19 confinement: A transcultural study
2021| Alcázar-Córcoles, M. A., Bouso, J. C., Dos Santos, R. G., Hallak, J. E., Ona, G., Révész, D., Rocha, J. M., Rossi, G. N.
This survey study (n=2,974) investigated the relationship between lifetime psychedelic use, personality traits, and mental health during the COVID-19 confinement, and found that regular use was associated with less psychological distress, less peritraumatic stress, and more social support. Psychedelic drug users also scored higher on the novelty-seeking and self-transcendence scales, but lower on cooperativeness.
A Gratuitous Grace: The Influence of Religious Set and Intent on the Psychedelic Experience
2018| Glasser, C., Neitzke-Spruill, L.
This survey study (n=119) examined the relationship between psychedelic-induced mystical experiences and religious identity and found that being religious and taking psychedelic drugs with religious intent were significantly related to having stronger mystical experiences when using psychedelics.
Psychological variables implied in the therapeutic effect of ayahuasca: A contextual approach
2018| Alcázar, M. A., Bouso, J. C., Franquesa, A., Gandy, S., Sainz-Cort, A., Soler, J.
This retrospective survey study (n=122) compared non-ayahuasca users with ayahuasca users in Decentering, Values, and Public control of the experience of self, and found that although participants who had taken ayahuasca on more than 15 occasions scored higher on Decentering than all other participants, there was no direct correlation between the number of ayahuasca sessions and any of the psychological variables.
Lifetime use of psychedelics is associated with better mental health indicators during the COVID-19 pandemic
2021| Cavanna, F., Cuiule, J., Di Tella, R., González, P., Milano, V., Pallavicini, C., Tagliazucchi, E.
This survey (n=5618) found that those who used psychedelics (32% of the sample) had increased positive affect and more resilient personality traits (e.g. plasticity) during the COVID-19 pandemic.
The psychology of philosophy: Associating philosophical views with psychological traits in professional philosophers
2021| Anderson, D., Yaden, D. B.
This survey study (n=314) investigated professional philosophers' worldviews in relation to psychological traits, such as personality, well-being, lifestyle, transformative life experiences, and psychedelic use. Amongst other results, they found an association between Hard Determinism (no free will) and more depression - as well as lower life satisfaction, and that psychedelics use was associated with non-realist/subjective view of moral and aesthetic value judgments, while transformative or self-transcendent experiences predicted theism and idealism as their worldview.
Clinical Studies of Lysergic Acid Diethylamide
1986| Anderson, E. W., Rawnsley, K.
This early clinical study (1954) investigated the dose-range effects of LSD (10-600μg) administered to patients and clinical staff (n=23) across 54 different research sessions and found that its effects entail highly potent perceptual alterations that are sensitive to the environment and variable across different individuals. They also note the emergence of phenomena such as enhanced sexual arousal and ego-dissolution and highlight its utility at illuminating basic personality structures but remain inconclusive as to whether it has therapeutic benefit in response to continued administration.
Mental changes experimentally produced by d-lysergic acid diethylamide tartrate
1988| Deshon, H. J., Rinkel. M., Solomon, H. C.
This early open-label investigation (1952) reports observations of mental changes in normal adults (n=15) produced by LSD (70μg/70kg) across 17 repeated experiments. Alterations were observed in the areas of thinking and speech, emotion, mood and affect, sensory and time perception, behavior, morbid ideas, and sensory experiences, and neurological signs, which were taken to reflect a schizophrenic-like state.
LSD-induced entropic brain activity predicts subsequent personality change
2016| Carhart-Harris, R. L., Feilding, A., Kaelen, M., Lebedev, A. V., Lövdén, M., Nilsson, J., Nutt, D. J.
This counterbalanced, placebo‐controlled within-subjects study (n=20) investigated whether the combination of administering LSD (75µg/70kg) while listening to music can induce changes in entropic brain activity during resting state, and cause subsequent changes in personality structure. Results indicated that acute increases in brain entropy affecting the disintegration of functional connectivity within sensory and higher-order networks were predictive of subsequent increases in trait openness measured 2 weeks later, and this relationship was enhanced by listening to music.
Psychological and neuropsychological assessment of regular hoasca users
2016| Areco, K., Barbosa, P., Bogenschutz, M. P., da Silveira, D. X., Hoy, R., Pommy, J. A., Strassman, R. J., Thoma, R.
This study (n=57) assessed the socio-economic status, mood, personality traits, impulsiveness, drug use, quality of life, extrinsic and intrinsic religiosity, and neuropsychological function of ayahuasca users and non-users. The findings indicate that religious use of ayahuasca does not adversely affect neuropsychological functioning and may have positive effects on substance abuse and mood.
Exploring the relationship between microdosing, personality and emotional insight: A prospective study
2021| Bright, S. J., Dressler, H. M., Polito, V.
This prospective survey study (n=24) explored the relationship between microdosing, personality change, and emotional awareness. Conscientiousness increased, while neuroticism decreased across these time points and correlated negatively with duration of prior microdosing experience. Extraversion correlated positively with both duration of prior microdosing experience and lifetime number of microdoses.
Prediction of MDMA response in healthy humans: a pooled analysis of placebo-controlled studies
2021| Harder, S., Ley, L., Liechti, M. E., Studerus, E., Vizeli, P.
This pooled-data analysis (n=194) of healthy participants of RCTs with MDMA (75mg-125mg) found that MDMA plasma concentration was the strongest predictor of outcomes. The more active the CYP2D6 enzyme, the lower the plasma concentration. And the higher the score on Openness, the more closeness and two subscales of an altered states of consciousness questionnaire (5D-ASC).
Examining changes in personality following shamanic ceremonial use of ayahuasca
2021| Campbell, W. K., Carter, N. T., Miller, J. D., Weiss, B.
This open-label study (n=256) found that directly after an ayahuasca retreat, and three months later, the personality of the participants was changed. The strongest finding was for neuroticism, but noted should be that there was no control group.
Self-blinding citizen science to explore psychedelic microdosing
2021| Blemings, A., Carhart-Harris, R. L., Erritzoe, D., Feilding, A., Kartner, L., Nutt, D. J., Rosas, F. E., Szigeti, B.
This self-blinding experiment (n=191) finds that the placebo and microdosing groups both experienced similar improvements in self-rated psychological well-being and cognitive function (e.g. mood, energy, creativity) after four weeks. This study provides more evidence that microdosing benefits can be attributed to expectancy (placebo) effects.
Prosocial effects of MDMA: A measure of generosity
2015| de Wit, H., Delton, A. W., Kirkpatrick, M. G., Robertson, T. E.
This placebo-controlled within-subjects study (n=32) investigated the dose-dependent effects of MDMA (35-70mg/70kg) on generosity, as measured by their willingness to trade-off personal welfare in favor of the welfare of someone else. The higher dose of MDMA increased generosity in relation to a close friend but not a stranger, whereas the lower dose did not affect generosity toward the friend but slightly increased generosity toward a stranger. These results are in line with the prosocial effects of oxytocin, which promotes trust amongst members of a social ingroup but not the out-group.
Recreational use of psychedelics is associated with elevated personality trait openness: Exploration of associations with brain serotonin markers
2019| Carhart-Harris, R. L., Erritzoe, D., Fisher, P. M., Frokjaer, V. G., Knudsen, G. M., Smith, J. M.
This cross-sectional study (n=45) evaluates associations between recreational use of psychedelics and MDMA and (a) personality measures and (b) key markers of cerebral serotonergic signaling (serotonin transporter and serotonin-2A-receptor binding).
Neuroticism is associated with challenging experiences with psilocybin mushrooms
2017| Barrett, F. S., Griffiths, R. R., Johnson, M. W.
This survey study (n=2,974) found that neurotic individuals may be more likely to have a challenging experience with psilocybin.
Personality, Psychopathology, Life Attitudes and Neuropsychological Performance among Ritual Users of Ayahuasca: A Longitudinal Study
2012| Alcázar, M. A., Araújo, D. B., Barbanoj, M. J., Barbosa, P., Bouso, J. C., Cutchet, M., Fernández, X., Fondevila, S., Fábregas, J. M., González, D., Riba, J.
This longitudinal field study (n=242) assessed personality, mental health, life attitudes, and neuropsychological performance in a large number of long-term ritual ayahuasca users and control participants that were matched for age, sex, educational level, and religious background. Long-term ayahuasca use indicated a lower presence of psychopathological symptoms, better performance in neuropsychological tests, higher degrees of spirituality, and better psychosocial adaptation as reflected by some attitudinal traits such as Purpose in Life and Subjective Well-Being, and benefits on mental health were still observable in a one-year follow-up.
Effects of psilocybin therapy on personality structure
2018| Carhart-Harris, R. L., Erritzoe, D., Kaelen, M., MacLean, K. A., Nour, M. R., Nutt, D. J., Roseman, L.
This open-label study (n=20) found that dosages of psilocybin (10, 25mg) in a supportive setting, for those with treatment-resistant depression (TRD), changed their personality. At 3-month follow-up, Neuroticism was decreased, Extraversion and Openness were increased. The changes were similar (but more pronounced) to changes after conventional antidepressant treatment.
The effect of acutely administered MDMA on subjective and BOLD-fMRI responses to favourite and worst autobiographical memories
2014| Bloomfield, M., Bolstridge, M., Carhart-Harris, R. L., Curran, H. V., De Meer, I., Erritzoe, D., Feilding, A., Ferguson, B., Kaelen, M., Moran, R. J., Newbould, R. D., Nutt, D. J., Stewart, L., Tanner, M., Wall, M. B., Williams, T. M.
This double-blind, placebo-controlled, within-subjects fMRI study (n=19) investigated the effect of MDMA on the recollection of favorite and worst autobiographical memories (AMs). Positive memories were rated as more positive and negative memories as less negative after MDMA use. Several brain regions were found to be active during AM recollection and related to memory valance.
Increased nature relatedness and decreased authoritarian political views after psilocybin for treatment-resistant depression
2018| Carhart-Harris, R. L., Lyons, T.
A pilot study (n=14) on how psychedelics increase nature relatedness and decrease authoritarianism. Although the active participants (n=7, with treatment-resistant depression) increased on both, their final scores on those measures were very similar to that of the non-treated (non-depressed) group.
This section compares the research with psychedelics to other therapies, medicines, or treatments.
This section highlights the various measures used and their use in research.
Who are the top researches in this area, the ones who have done the groundbreaking research.
What do we not know at this time? Where are the gaps in our knowledge and are we closing it?
The companies that are actively engaged in researching this topic or (planning to) provide therapy focussed on this topic.
This section highlights everything done outside of academia, from popular press to books and non academic research.