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Leadership

The Mind Unleashed: one of Metanoia's twelve dimensions of human capacity

Read this first. This page is education, not instructions to use. Metanoia does not supply any substance. In the United States, most of the substances discussed here are Schedule I under federal law (21 CFR 1308.11), their legal status differs between countries and between US states, and none of this is legal advice. Nothing here is medical advice, and nothing here describes or recommends a dose. "Healthy adults" means people with no diagnosed psychiatric or major medical condition, the population Metanoia studies. No controlled study below measured leadership itself, much of the evidence comes from surveys in which people described their own experience, and the text states the design and who did the rating each time, because that changes what a result can mean for healthy adults.

What it is

Metanoia's working definition of leadership is the capacity to guide, influence or coordinate others toward a shared goal. The definition already shows why this dimension is hard to study. Most human capacities sit inside one person and can be tested by asking that person to do something. Leadership sits between people. Someone nobody follows is not leading, and whether anyone follows is something only the others can report.

Research on the topic separates at least three things. Leader emergence is whether a person ends up in charge of a group. Leadership effectiveness is whether the group does well under that person. Leadership behavior is what the person does, often scored as a "transformational" or "transactional" style. A trait can predict one of these and miss the others, which is why a large meta-analysis of 73 samples examined emergence and effectiveness as separate criteria [1].

Who does the rating matters as much as what is rated. A 2022 meta-analysis reported that leaders' own ratings of their transformational style correlated only 0.27 with ratings made by others (23 effect sizes, 2,784 people), a figure it took from an earlier meta-analysis of self-other agreement [2]. Emotional intelligence measured by performance tests, where the person solves emotion problems rather than describing themselves, related to transformational leadership at 0.13 when others did the rating (6 samples) and at 0.29 when leaders rated themselves (17 samples) [2]. Leadership researchers therefore favor ratings from colleagues, reports and supervisors, often called 360-degree ratings, over self-ratings.

This page is built differently from the other dimension pages, because the evidence is different. No controlled study turned up in the searches that measured leadership as an outcome after a psychedelic in healthy adults, and the closest items are surveys in which managers described the effect themselves. What exists is a set of studies that measured traits leadership research links to leading, namely openness, flexibility of thinking, handling of emotion and empathy. The page works in two steps: what has been measured after psychedelics, then what leadership research says about those same traits. Joining the two is an inference, and each time the page makes that join, it says so.

What is known

The short version. No controlled study has measured leadership after a psychedelic in healthy adults. The nearest evidence concerns four traits. For openness there is one careful study without a placebo comparison, one weaker replication and a microdosing trial in which the active group could not be told apart from placebo. Controlled results on flexibility of thinking point in both directions, evidence on emotion regulation in healthy adults is close to empty, and the clearest result on empathy is acute and fades with the drug. The links between these traits and leadership are modest and come from research with no psychedelics. In one survey of managers, about four in ten of those who had tried a psychedelic described a positive effect on their leadership, but a survey cannot separate effect from expectation.

Step one: what has been measured in healthy adults

Ratings by other people. Three studies come close to the idea of an outside rating. In an early double-blind study, 36 hallucinogen-naive adults who were active in religious or spiritual life took part. Thirty received a high psilocybin dose and an active comparison drug (methylphenidate) in separate sessions, in counterbalanced order, and six more received the comparison drug twice before an unmasked psilocybin session. Community observers, three adults per participant, rated changes in attitudes and behavior by telephone. Observer data exist for 26 participants, and the observers saw their earlier ratings before rating again. The observer score rose by 2.42 after psilocybin and was unchanged after the comparison drug, a difference the authors call small but significant [3]. A later trial gave 75 healthy adults either high or very low psilocybin doses inside a six-month program of meditation and spiritual practice. Each participant named three adults who stayed in contact, and an interviewer scored 13 behaviors by telephone. The authors report that the observer total score followed the same pattern as the self-reports, with the largest change in the high-dose group that received the most support. They give a mean effect size near 1.0 across all 23 longitudinal measures, a figure that is not specific to the observer scores. They also note that the extra support for spiritual practice cannot be separated from psilocybin in the high-support group, because the design had no low-dose arm with that support [4]. In the five-day meditation retreat covered on the Mindfulness page, one significant other per participant (37 observers for 39 analysed participants) completed a life-change questionnaire four months later. The pattern resembled the self-reports but was less marked [5].

None of the three measured leadership. The observers were chosen by the participants and knew them personally, so the ratings came from family, friends and some colleagues rather than from people the participant led.

Openness. Openness to experience covers curiosity, imagination, aesthetic interest and tolerance of other people's views. The best-known result is a pooled analysis of two double-blind studies in 52 hallucinogen-naive adults who received a high psilocybin dose under supportive conditions. On a standard personality inventory, openness rose by 2.8 points (p = 0.023) at one to two months. The 30 participants who had a complete mystical-type experience rose by 5.7 points and were still 4.2 points above baseline at about 16 months (p = 0.050). The other 22 did not change. Across all 52, none of the other four personality domains changed significantly. In a subgroup of 30 whose first session involved a comparison substance or a low dose, openness did not move after that session [6]. There was no placebo group for the high-dose session. The sample was small, 90 percent of the participants took part regularly in religious or spiritual activity, and the authors called for replication in larger and more varied groups [6].

Later work gives a mixed picture. In 256 guests at ayahuasca retreat centers, followed for three months, the largest change was a fall in neuroticism, and informants (110 of them) saw it too. Openness changed, but not robustly once expectation and suggestibility were taken into account, and baseline openness was already high, which leaves little room to rise. The study had no control group [7]. In an open-label study of 20 patients with treatment-resistant depression, openness also rose after psilocybin therapy, but that is a clinical group, there was no control group, and the rise did not differ between patients who improved and those who did not [8]. In a self-blinding citizen-science microdosing trial, 191 people completed the study and openness in the active group rose by 0.9 points over the four-week dosing period, but the authors report no significant difference between active and placebo groups on any scale at any time point [9]. A 2026 meta-analysis of microdosing in healthy adults included 24 studies with 3,681 participants, but only 6 entered the quantitative analyses, among them two randomized trials with 117 participants in all, where effects on depression, anxiety and stress did not differ reliably from placebo. The authors concluded that observational studies showed improvements likely influenced by expectancy or lifestyle, and that the randomized evidence remains inconclusive [10]. A 2020 review of 34 experimental studies with follow-up of at least two weeks reported enduring changes in personality and attitudes after classic psychedelics [11].

For scale, a 2017 meta-analysis of 207 studies of personality change through intervention found an average change of d = 0.37 over about 24 weeks, with emotional stability changing most. The focus was mainly clinical interventions, only 19 of the studies used non-clinical samples, and the estimate fell to as little as d = 0.21 under corrections for publication bias. The authors themselves ask for ratings by friends or interviewers who took no part in the intervention [12].

Flexibility of thinking. Cognitive flexibility is the ability to shift between mental sets, measured by card-sorting and task-switching tests. Psychological flexibility is the ability to stay in contact with difficult thoughts and still act on what matters to the person. The results conflict.

Among 48 people tested within 24 hours of an ayahuasca ceremony, scores on cognitive flexibility measures were higher than their own earlier scores, but there was no control group [13]. Among ayahuasca ceremony attendees, 57 were tested before and the day after, and only 31 completed the four-week follow-up. Convergent thinking scored higher at four weeks than before, divergent thinking did not change, and some participants reported diagnoses such as depression. There was no control group [14]. In an online survey of 1,342 university students, those reporting lifetime or recent psychedelic use did better on a card-sorting task than non-users, and the number of lifetime uses made no difference, so the design cannot separate use from the kind of person who uses [15]. Against these, a placebo-controlled crossover in 24 healthy volunteers found worse card-sorting performance 24 hours after a low dose of LSD, alongside better episodic memory and verbal fluency. The p values on the authors' poster are not corrected for multiple comparisons, and the full paper was not accessible [16]. In the acute phase the picture is clearer: a meta-analysis of 13 psilocybin studies (42 effect sizes) found slower reaction times (Hedges' g = 1.13) with accuracy not significantly changed, and the three studies of cognitive flexibility showed impairment, including one microdose study [17].

For psychological flexibility, a cross-sectional online survey of 985 people who had used a psychedelic and reported a change in depression or anxiety afterward found that increases in psychological flexibility statistically accounted for the link between mystical and insightful experience and later falls in depression and anxiety. Leadership was not the outcome, the sample was selected on that reported change, and the reports were retrospective [18]. Among 81 people who planned to start microdosing (253 at baseline, so 68 percent dropped out), a measure of experiential avoidance fell over four weeks. About 46 percent reported a psychiatric diagnosis, so this was not a healthy-adult sample in Metanoia's sense. Positive expectation at the start predicted the later gain in well-being, which the authors read as a sign of a placebo response, and openness did not change [19].

Handling emotion. Emotion regulation is the set of ways a person influences which emotions they have and how they show them. In healthy adults the evidence is thin. A preregistered, double-blind, placebo-controlled crossover of psilocybin microdosing found no difference from placebo in emotion processing or in depression and anxiety symptoms, with Bayes factors of 0.15 to 0.38 that favor no difference. Baseline scores were already in the normal range, and participants broke the blind in the second block [20]. In adults with severe ADHD symptoms, a clinical group, a naturalistic study found early gains in reappraisal and expressive suppression among people starting microdosing, but once a comparison group on conventional ADHD medication was added only the change in suppression persisted [21]. In 21 healthy volunteers, acute psilocybin reduced the feeling of being socially excluded and reduced activity in a brain region involved in social pain. Ratings of belonging and self-esteem did not differ from placebo, and only the acute phase was measured [22]. In the searches done for this page, no placebo-controlled trial in healthy adults used an emotion-regulation measure as its main outcome weeks after the experience.

Empathy. Empathy has an emotional part, sharing what another person feels, and a cognitive part, working out what another person thinks. In 32 healthy volunteers tested about 160 minutes after psilocybin or placebo, emotional empathy rose, cognitive empathy did not, and answers to hypothetical moral dilemmas (24 people) did not change [23]. Among 55 attendees of a psilocybin retreat, emotional empathy was higher the morning after and some empathy measures were still higher a week later, but only 22 people completed the last test and there was no control group [24]. In the microdosing study in adults with ADHD, perspective-taking rose, but it rose in the comparison group on conventional medication too, and the other empathy scales did not change [21].

Step two: what leadership research says about the same traits

A meta-analysis of 222 correlations from 73 samples found these corrected correlations of the five personality factors with leadership: openness 0.24, neuroticism minus 0.24, extraversion 0.31, conscientiousness 0.28 and agreeableness 0.08. The observed correlations were smaller, for example 0.16 for openness and 0.22 for extraversion. Extraversion was the only trait that held across business, military and student samples, and no study used group performance as the criterion, only ratings of perceived leadership. All five traits together gave a multiple correlation of 0.48 [1]. A second meta-analysis, of 384 correlations from 26 studies on transformational and transactional styles, again found extraversion strongest and described the overall associations as weak [25]. A meta-analysis of motivation to lead (100 primary studies) suggested that traits usually seen as helpful, including openness, may have a darker side that travels through the wish to take charge [26]. A corrected correlation of 0.24 means openness accounts for roughly 6 percent of the differences in leadership across people, and under 3 percent on the observed value. The five traits together account for about 23 percent. Extraversion, the strongest correlate, did not change in the psilocybin study above [6], and in the ayahuasca sample its rise was not robust once expectation was considered [7].

For emotion, the 2022 meta-analysis cited earlier puts the link between emotional intelligence and others' ratings of transformational style at 0.13 [2]. A study of 226 undergraduates, 196 of them analysed, tested habits of emotion regulation against performance on short leadership exercises. Taken one at a time, reappraisal correlated with better performance (r = 0.19), suppression with worse (r = minus 0.18) and empathy with better (r = 0.19). When the measures were entered together with controls, only suppression remained a significant predictor (standardized coefficient minus 0.15), and reappraisal and empathy did not. The authors flag a scale with low reliability, and students working through low-fidelity tasks are not leaders in organizations [27]. For flexibility, one multilevel study of 437 people in 74 military teams reported that a leader's cognitive flexibility predicted followers' innovative behavior through a sense of empowerment, a result known here from its abstract only [28]. We found no meta-analysis linking psychological flexibility to leadership effectiveness.

Putting the steps together (inference)

A chain of four links would have to hold before a psychedelic could be said to affect leadership. The trait would have to change and stay changed. The changed trait would have to alter behavior at work. Other people would have to notice. And the group would have to do better. For openness, the first link has partial and contested support. For empathy it has acute support only. The second, third and fourth links have not been tested after any psychedelic. The leadership research that supports the other end of the chain describes how traits differ between people who lead and people who do not. It does not show that changing a trait changes leadership.

Two cautions follow. The controlled microdosing trials in healthy adults show no change that survives comparison with placebo, and acute effects on tasks that call for executive control are a different question from lasting change in a trait, so the two bodies of evidence should not be blended.

What managers and founders report

The most direct data come from surveys. A 2023 study recruited 9,732 US and UK adults through an online panel built to match national profiles, without mentioning psychedelics in the study description. Of the 3,150 whose main role at work was management, 559 had tried a psychedelic. Asked in one open question whether and how it had affected their leadership, 227 of the 559 (40.6 percent) described a positive impact, 324 (58.0 percent) none or an unclear answer, and 8 (1.4 percent) a negative one. Among psychedelic users, greater psychological insight during the most intense experience went with a higher chance of reporting a positive impact (adjusted odds ratio 3.49 per standard deviation of the insight score, n = 551). The authors state that causality cannot be inferred. The survey had one open question, no non-user comparison on leadership, no measure of leadership by anyone but the respondent, and no information on whether use came before or after the person became a manager. Two authors disclose commercial ties: consulting for three companies, and co-founding another [29].

An analysis of a federal survey of 168,920 full-time employed US adults from 2006 to 2014 found that past-year LSD use rose faster among business managers than among non-managers. The author reads this as growing interest in competitive advantage, which is an interpretation, because a survey of use cannot show motive or benefit. Only the abstract was read [30]. Press coverage adds anecdote. A 2022 feature on startup founders carries a headline saying founders report that psychedelics make them better leaders. It quotes one founder describing an ayahuasca ceremony as preparation for his career, cites no survey of psychedelic use among founders, and three of its five interviewees run businesses built around such experiences [31].

The microdosing culture question

Public stories about microdosing at work, often tied to Silicon Valley, rest mostly on journalism and personal testimony. In the sources read for this page, no study sampled technology workers specifically. What the research does show is a gap between self-selected and controlled evidence.

On the optimistic side, a forum-recruited sample of microdosers scored higher than non-microdosers on open-mindedness and wisdom and lower on dysfunctional attitudes, but the design cannot show cause. The open-mindedness difference was the smallest (d = 0.25, interval 0.02 to 0.47), against about 0.5 for the others [32]. In the reports of 278 microdosers recruited from Reddit, the commonest coded benefits were improved mood (26.6 percent) and improved focus (14.8 percent), and the commonest coded problems were illegality (29.5 percent) and physical discomfort (18.0 percent). These are shares of coded reports, not of respondents [33]. On the controlled side, the self-blinding citizen-science trial found improvement in the active group and, on some measures, in the placebo groups, with no significant difference between them, and participants guessed correctly on 72 percent of daily assessments against 63 percent expected by chance, which allows expectation to explain small acute differences [9]. A double-blind trial of 34 people starting a psilocybin-mushroom regimen, measured for one week per condition, found no evidence of better well-being, creativity or cognition and a few small changes toward impairment. The blind was broken in 75 percent of weeks, and the authors concluded that expectation underlies at least some of the anecdotal benefit [34]. An observational study of 98 microdosers (63 completed the test battery at both ends) found reduced depression and stress but slightly higher neuroticism after six weeks, with no placebo group and no change in openness. A companion survey found that people expected wide benefits that did not match what actual users reported [35]. A critical review of 57 human studies concluded that observational studies report more benefit and experimental trials more null results, and that the evidence remains inconclusive [36].

The proper statement for healthy adults is that randomized trials show no consistent benefit of microdosing over placebo, and that the gap between observational and controlled studies is itself a subject of research [10]. Leadership adds a further problem. The outcome is relational, and the microdosing studies relied on self-ratings and lab tasks.

What is not known

No study has measured leadership after a psychedelic with ratings from the people who work with the person, which is the design leadership research itself trusts. The observer studies that exist used personally chosen raters and general life-change scales. Nothing is known about whether any change in openness, flexibility or empathy carries into behavior at work, whether it lasts a year, or whether it helps a team.

The openness result rests mostly on one pooled analysis of 52 people, most of them regular participants in spiritual life, without a placebo session for the high dose [6]. The ayahuasca replication was uncontrolled and drew on retreat guests who started with high openness [7]. Blinding is a standing problem, since a participant who has had a strong experience knows it, and in one prospective microdosing study positive expectation predicted improved well-being [19].

The link from traits to leadership is itself modest and mostly correlational. Whether lowering neuroticism or raising openness in an adult makes them lead better has not been shown by any study read here. Measurement is a further weakness. Self-ratings of leadership agree poorly with ratings by others [2], so any study that asks only the person is close to uninformative on this dimension.

What Metanoia seeks to learn. Metanoia is a California 501(c)(3) public charity advancing the science of natural psychedelics for personal growth and human flourishing in healthy adults. Not treating illness. Expanding potential. The gaps above point to a general research design: a validated measure that includes behavior items about taking and avoiding initiative with others, and an optional rating by a person the respondent names, with that person's consent and a separate privacy review. It would follow people over time under shared reporting standards, with records kept under full legal authorization and with Metanoia supplying no substance. This page found no instrument built that way, and it describes no Metanoia study. A naturalistic observational cohort studied that way could help answer questions the literature leaves open:

  1. Do people who join the cohort differ from the general population on ratings by others, before any exposure?
  2. Does a rating by a colleague or friend change over a year in people with a recorded purpose of use, compared with people who report no use?
  3. Do changes in openness or empathy, if they appear, show up in what others observe?
  4. How much of any change survives once expectation is measured?
  5. Do self-ratings and ratings by others move together, and which is more trustworthy?

None of this means Metanoia expects a particular answer. A null result would be as useful to publish as a positive one. This dimension may stay thin for some time.

Compared with other paths

Leadership development is an established field, and its evidence is far larger than the psychedelic evidence.

Leadership training. Pooled across 335 independent samples that used employee data and four criteria, leadership training showed positive effects on reactions (δ = 0.63, from only 7 samples, interval 0.12 to 1.15), learning (0.73), transfer to the job (0.82) and results (0.72). Within results, organizational outcomes averaged 0.75 and subordinates' outcomes 0.22 [37]. Programs that used 360-degree feedback did not differ significantly from those using single-source feedback, so the review does not show that multi-rater assessment validated the programs. The authors report funding from a leadership-development institute.

Coaching. One review of 18 studies reported an overall effect of g = 0.66 (95 percent confidence interval 0.39 to 0.93) with high heterogeneity (I² = 87 percent), including performance and skills (g = 0.60). Without one study the overall effect fell to 0.51 and the effect on performance and skills to 0.19. Within-subject designs gave larger effects (1.15) than the others (0.39), and most studies relied on self-reported outcomes [38]. A second review, of 17 studies, gave an overall effect of 0.36 (90 percent confidence interval 0.16 to 0.50). Effects were 0.88 across 9 studies without multi-source feedback and 0.21 across 7 that used it, though the first estimate has a wide interval and the authors urge caution [39].

360-degree feedback. Across 24 longitudinal studies of multisource feedback, most of them without a control group, ratings improved only a little after leaders received it. Corrected mean effects were 0.15 for direct reports (21 studies), 0.05 for peers (7), 0.15 for supervisors (10) and minus 0.04 for self-ratings (11), and for every rater source except supervisors the 95 percent confidence interval included zero. The supervisor correction used an assumed reliability [40]. How well 360-degree ratings measure leadership is a separate question that this evidence does not address.

Other routes to trait change. The 2017 review above found that interventions of many kinds shift personality traits, mostly emotional stability [12]. The mindfulness route is covered on the Mindfulness page. In the manager survey, 70.9 percent of managers who had practiced mindfulness meditation described a positive effect on leadership, against 40.6 percent for psychedelics, with the same limits on both [29].

Putting it together, established training and coaching have pooled evidence of small to large average effects (0.19 to 0.82 across the reviews above), and 360-degree feedback has small effects on later behavior. Several of these figures rest on self-reports or on few studies. No study has compared a psychedelic route with any of these, and the psychedelic evidence is weakest exactly where leadership is defined, in what other people see.

Sources

Grade key: 1 = peer-reviewed primary study of any design, systematic review, meta-analysis or official record. 2 = peer-reviewed narrative, integrative or scoping review. 3 = preprint, press, community or grey source. 4 = traditional text. Grade describes the type of source, and the design and its limits are given in the text. "Full text" means read in full by Metanoia between 1 and 4 October 2026. Where the version read was an authors' manuscript or an advance online draft, the entry says so. "Abstract only. Full text not accessible" means the full paper could not be opened.

  1. Judge TA, Bono JE, Ilies R, Gerhardt MW. J Appl Psychol 2002, 87(4):765-780. DOI 10.1037/0021-9010.87.4.765 Grade 1. Meta-analysis, 222 correlations from 73 samples. Full text (publisher's PDF copy, 16 pages). Note: Leadership behavior includes setting a direction, rewarding good work or attending to individuals.
  2. Hsu N, Newman DA, Badura KL. J Intell 2022, 10(4):104. DOI 10.3390/jintelligence10040104 Grade 1. Meta-analysis of emotional intelligence and transformational leadership, original and extracted correlations. Full text (methods, correlation table and results sections). The 0.27 self-other figure appears in a table note attributed to Lee and Carpenter 2018, which was not read.
  3. Griffiths RR, Richards WA, McCann U, Jesse R. Psychopharmacology 2006, 187(3):268-283. DOI 10.1007/s00213-006-0457-5 Grade 1. Double-blind crossover study, 36 volunteers (30 in the full crossover), community observer ratings at 2 months for 26. Full text (publisher's PDF copy, with abstract, methods, observer assessment, discussion and limitations).
  4. Griffiths RR, Johnson MW, Richards WA, et al. J Psychopharmacol 2018, 32(1):49-69. DOI 10.1177/0269881117731279 Grade 1. Randomized double-blind three-group trial, n = 75, 6-month follow-up with community observer ratings. Full text (methods, results summary and limitations). Note: The 13 behaviors scored by the interviewer included mental flexibility, interpersonal perceptiveness and caring, anger expression, compassion and self-confidence.
  5. Smigielski L, Kometer M, Scheidegger M, Krähenmann R, Huber T, Vollenweider FX. Sci Rep 2019, 9:14914. DOI 10.1038/s41598-019-50612-3 Grade 1. Randomized, double-blind retreat trial in meditators, n = 39. Full text (observer-rating and discussion sections). Note: The two scales with significantly higher scores were self-acceptance and quest for meaning. In the Zurich retreat trial, a habit of reappraising emotions predicted the character of the acute response, which runs in the opposite direction from the question here.
  6. MacLean KA, Johnson MW, Griffiths RR. J Psychopharmacol 2011, 25(11):1453-1461. DOI 10.1177/0269881111420188 Grade 1. Pooled analysis of two double-blind studies, n = 52, no placebo group for the high-dose session. Full text, read in full. Note: The rise of 2.8 points was on a scale where the average person scores 50 and the spread is 10.
  7. Weiss B, Miller JD, Carter NT, Keith Campbell W. Sci Rep 2021, 11:6653. DOI 10.1038/s41598-021-84746-0 Grade 1. Prospective naturalistic study, N = 256 (informants 110), no control group. Full text (results, discussion and limitations). Note: The retreat centers were in Central and South America. The fall in neuroticism was about one standard deviation of change in the week after and 0.85 at three months.
  8. Erritzoe D, Roseman L, Nour MM, et al. Acta Psychiatr Scand 2018, 138(5):368-378. DOI 10.1111/acps.12904 Grade 1. Open-label study in 20 patients with treatment-resistant depression (clinical population), no control group. Full text.
  9. Szigeti B, Kartner L, Blemings A, et al. eLife 2021, 10:e62878. DOI 10.7554/eLife.62878 Grade 1. Self-blinding citizen-science trial, 191 completers. Full text (results, blinding integrity and limitations sections).
  10. Meshkat S, Leung M, Meshkat S, et al. CNS Drugs 2026, 40(10):1369-1393. DOI 10.1007/s40263-026-01325-5 Grade 1. Systematic review and meta-analysis, 24 studies, 3,681 participants, 6 studies in the quantitative analyses. Abstract only. Full text not accessible.
  11. Aday JS, Mitzkovitz CM, Bloesch EK, Davoli CC, Davis AK. Neurosci Biobehav Rev 2020, 113:179-189. DOI 10.1016/j.neubiorev.2020.03.017 Grade 1. Systematic review, 34 experimental studies. Abstract only. Full text not accessible. Note: The review also asked for larger samples, longer follow-up and stronger controls.
  12. Roberts BW, Luo J, Briley DA, Chow PI, Su R, Hill PL. Psychol Bull 2017, 143(2):117-141. DOI 10.1037/bul0000088 Grade 1. Meta-analysis, 207 studies, primary focus on clinical interventions. Full text (the advance online draft hosted on a third-party site, not the printed version, with abstract, methods, main results and limitations).
  13. Murphy-Beiner A, Soar K. Psychopharmacology 2020, 237(4):1161-1169. DOI 10.1007/s00213-019-05445-3 Grade 1. Pre-post field study, n = 48, no control group. Abstract only. Full text not accessible.
  14. Uthaug MV, van Oorsouw K, Kuypers KPC, et al. Psychopharmacology 2018, 235(10):2979-2989. DOI 10.1007/s00213-018-4988-3 Grade 1. Prospective field study, 57 at baseline and the day after, 31 at four weeks, no control group. Full text. Note: Convergent thinking is the kind that finds one right answer.
  15. Todesco S, Allan Z, Liu MYM, Schütz C. Prog Neuropsychopharmacol Biol Psychiatry 2026, 149:111888. DOI 10.1016/j.pnpbp.2026.111888 Grade 1. Cross-sectional online survey with a card-sorting task, n = 1,342 students. Abstract only. Full text not accessible.
  16. Wießner I, Olivieri R, Falchi M, et al. Eur Neuropsychopharmacol 2022, 58:7-19. DOI 10.1016/j.euroneuro.2022.01.114 Grade 1. Randomized, double-blind, placebo-controlled crossover, n = 24. Abstract only. Full text not accessible. The authors' poster for the study (grade 3) was also read. Note: The crossover also found more perseveration on the card-sorting task.
  17. Yousefi P, Lietz MP, O'Higgins FJ, et al. Psychopharmacology 2025, 242(6):1171-1196. DOI 10.1007/s00213-024-06742-2 Grade 1. Systematic review and multilevel meta-analysis, 13 studies, 42 effect sizes. Full text (abstract and cognitive-flexibility sections).
  18. Davis AK, Barrett FS, Griffiths RR. J Contextual Behav Sci 2020, 15:39-45. DOI 10.1016/j.jcbs.2019.11.004 Grade 1. Cross-sectional online survey, n = 985 people who had used a psychedelic, included because they reported a change in depression or anxiety. Design limit: retrospective, no control. Full text.
  19. Kaertner LS, Steinborn MB, Kettner H, et al. Sci Rep 2021, 11:1941. DOI 10.1038/s41598-021-81446-7 Grade 1. Prospective web survey of people planning to microdose, n = 81 at the endpoint (253 at baseline), no control group, 46 percent with a psychiatric diagnosis. Design limit: self-selected, heavy dropout. Full text.
  20. Marschall J, Fejer G, Lempe P, et al. J Psychopharmacol 2022, 36(1):97-113. DOI 10.1177/02698811211050556 Grade 1. Preregistered double-blind, placebo-controlled crossover. Full text.
  21. Haijen ECHM, Hurks PPM, Kuypers KPC. Eur Psychiatry 2024, 67(1):e18. DOI 10.1192/j.eurpsy.2024.8 Grade 1. Naturalistic online prospective comparison in adults with severe ADHD symptoms (clinical population). Design limit: self-selected, clinical group. Full text.
  22. Preller KH, Pokorny T, Hock A, et al. Proc Natl Acad Sci USA 2016, 113(18):5119-5124. DOI 10.1073/pnas.1524187113 Grade 1. Double-blind, randomized, counterbalanced crossover, n = 21, acute effects. Full text (read on the PMC web page).
  23. Pokorny T, Preller KH, Kometer M, Dziobek I, Vollenweider FX. Int J Neuropsychopharmacol 2017, 20(9):747-757. DOI 10.1093/ijnp/pyx047 Grade 1. Double-blind placebo-controlled crossover, n = 32 (24 for the moral task), acute effects only. Full text (methods and results).
  24. Mason NL, Mischler E, Uthaug MV, Kuypers KPC. J Psychoactive Drugs 2019, 51(2):123-134. DOI 10.1080/02791072.2019.1580804 Grade 1. Field study at a retreat, 55, 50 and 22 participants at three time points, no control group. Full text (open-access publisher page, read on 2 October 2026).
  25. Bono JE, Judge TA. J Appl Psychol 2004, 89(5):901-910. DOI 10.1037/0021-9010.89.5.901 Grade 1. Meta-analysis, 384 correlations from 26 studies. Abstract only. Full text not accessible.
  26. Badura KL, Grijalva E, Galvin BM, Owens BP, Joseph DL. J Appl Psychol 2020, 105(4):331-354 (online 2019). DOI 10.1037/apl0000439 Grade 1. Meta-analysis, 100 primary studies, 1,154 effect sizes. Abstract only. Full text not accessible.
  27. Torrence BS, Connelly S. Front Psychol 2019, 10:1486. DOI 10.3389/fpsyg.2019.01486 Grade 1. Correlational study with low-fidelity leadership tasks, 226 undergraduates (196 analysed). Full text (methods, results and limitations).
  28. Cangialosi N, Odoardi C. Mil Psychol 2026, advance online, 1-14. DOI 10.1080/08995605.2026.2664919 Grade 1. Three-wave multilevel study, 437 personnel in 74 teams of one air force. Abstract only. Full text not accessible.
  29. Simonsson O, Stenfors CUD, Goldberg SB, Hendricks PS, Osika W. Front Psychol 2023, 14:1151626. DOI 10.3389/fpsyg.2023.1151626 Grade 1. Cross-sectional online survey, N = 9,732, managers n = 3,150, self-described impact on leadership. Design limit: one open question, self-described impact, cannot show cause. Two authors disclose commercial ties. Full text (read in full). Note: The online panel was built to match national age, sex and ethnicity profiles. Reported themes included patience, empathy, creativity, self-understanding and less hierarchical attitudes toward colleagues. For mindfulness meditation, 70.9 percent of managers who had tried it described a positive impact.
  30. Korman BA. Subst Use Misuse 2024, 59(2):159-166. DOI 10.1080/10826084.2023.2267105 Grade 1. Pooled cross-sectional analysis of a federal survey, 168,920 employed adults. Design limit: cross-sectional, shows use and not motive or benefit. Abstract only. Full text not accessible.
  31. Collins S. Fortune, 5 October 2022. https://fortune.com/well/2022/10/05/psychedelics-ayahuasca-in-the-startup-community/. Grade 3. Press feature, updated 27 June 2023. The whole article was read directly on 2 October 2026, with author and date taken from the page. Three of five interviewees have a commercial interest in the topic. Note: The article quotes one founder who says psychedelics are exploding in that community.
  32. Anderson T, Petranker R, Rosenbaum D, et al. Psychopharmacology 2019, 236(2):731-740. DOI 10.1007/s00213-018-5106-2 Grade 1. Preregistered cross-sectional comparison, microdosers recruited from online forums. Design limit: self-selected forum sample, cannot show cause. 594 microdosers and 315 non-microdosers. Read: the authors' accepted manuscript on a preprint server (full text), not the printed version.
  33. Anderson T, Petranker R, Christopher A, et al. Harm Reduct J 2019, 16:43. DOI 10.1186/s12954-019-0308-4 Grade 1. Qualitative coding of the reports of 278 microdosers recruited from Reddit. Design limit: self-reports coded by the authors, no control. Full text. Note: Increased anxiety was 6.7 percent of the coded problems. Self-efficacy, meaning motivation, confidence and a sense of control, made up 11.3 percent of the benefits, as free-text self-report.
  34. Cavanna F, Muller S, de la Fuente LA, et al. Transl Psychiatry 2022, 12:307. DOI 10.1038/s41398-022-02039-0 Grade 1. Double-blind placebo-controlled study, n = 34, one week per condition. Full text.
  35. Polito V, Stevenson RJ. PLoS One 2019, 14(2):e0211023. DOI 10.1371/journal.pone.0211023 Grade 1. Observational study of 98 microdosers followed for six weeks, plus a survey of 263 people on expectations. Design limit: observational, self-selected, no placebo group. Full text.
  36. Totomanova I, Haijen ECHM, Hurks PPM, Ramaekers JG, Kuypers KPC. Curr Opin Psychol 2025, 66:102129. DOI 10.1016/j.copsyc.2025.102129 Grade 2. Critical review of 57 human studies. Abstract only. Full text not accessible.
  37. Lacerenza CN, Reyes DL, Marlow SL, Joseph DL, Salas E. J Appl Psychol 2017, 102(12):1686-1718. DOI 10.1037/apl0000241 Grade 1. Meta-analysis, 335 independent samples. Design note: the authors report research funding from a leadership-development institute. Full text (publisher's PDF copy, with abstract, methods, results, tables and limitations). Note: Programs worked better when they used needs analysis, feedback, practice, spaced sessions, an on-site location and face-to-face delivery that was not self-administered.
  38. Theeboom T, Beersma B, van Vianen AEM. J Posit Psychol 2014, 9(1):1-18. DOI 10.1080/17439760.2013.837499 Grade 1. Meta-analysis, 18 studies. Design note: effects were smaller in controlled studies. Read: the authors' revised manuscript from a university repository, in full (the publisher's version was not read, and the abstract numbers match it). Note: Effects across outcomes ranged from 0.43 to 0.74: performance and skills (g = 0.60), well-being (0.46), coping (0.43), work attitudes (0.54) and goal-directed self-regulation (0.74).
  39. Jones RJ, Woods SA, Guillaume YRF. J Occup Organ Psychol 2016, 89(2):249-277. DOI 10.1111/joop.12119 Grade 1. Meta-analysis, k = 17. Read: the accepted manuscript from the University of Reading repository (methods, results, discussion and limitations), not the printed version.
  40. Smither JW, London M, Reilly RR. Pers Psychol 2005, 58(1):33-66. DOI 10.1111/j.1744-6570.2005.514_1.x Grade 1. Meta-analysis, 24 longitudinal studies. Read: the publisher's PDF copy hosted on a university site (abstract, methods, results, moderators and the start of the discussion).

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