Most of the psychedelic research you have heard about was done on people who were ill. Depression, addiction, post-traumatic stress, end-of-life distress. That work is serious, it is careful, and it is not the question this article is about.
The question here is older and much less studied. Can a person set out to change something about themselves, deliberately, and can anyone tell afterwards whether it happened?
The most cited finding in the field is also a lesson in measurement
Start with the study everyone quotes. In 2008, a Johns Hopkins team followed up 36 hallucinogen-naive adults fourteen months after a high-dose psilocybin session. Nearly two thirds said the experience had increased their well-being or life satisfaction. More than half rated it among the five most personally meaningful experiences of their lives.
Now the sentence that usually gets left out, taken from the paper itself. Of all the measures of personality, affect, quality of life and spirituality assessed across that study, only a scale measuring mystical experience showed a difference from screening.
So the well-being scales did not move. What moved was people's retrospective account of their own well-being, which is a different kind of evidence and should be labelled as one.
One thing in that programme did change on a measure. A companion paper reported a significant rise in the personality domain of openness after a high-dose session, and in participants who had a full mystical-type experience openness stayed above baseline more than a year later. Two conditions, both of them findings rather than decoration.
Hold those two results side by side and you have a measurement problem in miniature. In the 2008 study the well-being scales did not move. Later work from the same group did move instruments. A double-blind randomised study in 75 healthy participants, published in 2018, found large changes at six months on a range of longitudinal measures, including interpersonal closeness, gratitude, life meaning and purpose, and forgiveness, and on ratings by people who knew the participants. Those participants were also following a programme of meditation and spiritual practice, and the sample was fairly homogeneous, so the result does not carry over automatically to other healthy adults. The honest position is not that instruments cannot detect change in healthy adults. It is that what they detect depends heavily on which construct is measured and over what interval, and we have not identified work in which the change was assessed against a purpose the person stated in advance. With that in mind, it is worth asking what most existing instruments were built to do.
Built to detect a return to normal
A 2026 systematic review examined 67 studies of cognitive change after psychedelics, clinical and preclinical, from one day out to long-term follow-up. Psilocybin showed the most consistent signal, particularly in cognitive flexibility and attention.
Then the authors add the line that matters most to us. Improvements were seen more frequently in psychiatric populations than in healthy subjects, which, in their words, "may reflect a remediation of existing cognitive deficit rather than enhancement above normal functioning."
That hedge belongs in the quote and we keep it there. But take the possibility seriously for a moment. An instrument designed to detect the closing of a deficit is calibrated against a healthy baseline. Movement above that baseline is, by construction, off the top of its scale. If that is right, the field is not failing to find development in healthy adults. It is using rulers that stop where development would begin.
There is a second reason healthy adults are a different measurement problem, and it is quantitative. In one analysis, the identity of the person guiding the session explained about 0.8% of the variance in the acute experience in healthy participants, against about 13.6% in clinical ones. When you move from a clinical population to a healthy one, the person-level variables shrink by an order of magnitude and the protocol variables stay. A healthy volunteer is not a milder version of a patient. It is a different measurement regime, and the dominant terms in it happen to be the ones you can standardise.
Twelve dimensions, and what we honestly know about each
Metanoia organises this question into twelve dimensions of human growth. Creativity, problem-solving, emotional resilience, social connection, self-awareness, empathy, well-being, perception, learning and memory, mindfulness, nature connectedness, leadership.
It is a research frame. None of it is a promise. Some of these are in much better shape than others, and the differences are instructive.
Where the measurement is decent and the finding is specific. A double-blind randomised trial in healthy volunteers found that psilocybin significantly increased emotional empathy during the acute experience, and did not increase the cognitive kind. Moral decision-making was unaffected. That is a precise result, and the precision comes from a task-based instrument with sub-scales rather than a single score.
Where the evidence is real and the design is limited. Nature connectedness has a short validated measure and prospective self-report studies tracking shifts over weeks, months, and in one sample two years. None of it comes from a controlled trial in healthy adults. The most interesting detail is conditional: the shift tracked how much the natural surroundings actually featured in the experience, which makes it a question about setting and a question about measurement at the same time.
Where the popular story and the controlled evidence diverge. Creativity is the clearest case. A 2026 meta-analysis of microdosing in healthy adults pooled 24 studies and 3,681 participants. In randomised trials there was minimal impact on cognition, creativity or sustained mood, with depression, anxiety and stress all failing to separate from placebo. Observational studies did report improvements, which the authors attribute to expectancy and lifestyle. That is a null result in exactly our population, and we would rather bring it ourselves than have someone else bring it to us.
Where the instrument itself is unstable. Mindfulness looks easy to measure because validated questionnaires exist. The catch is that the factor structure of the main instrument shifts with meditation experience, and psychedelic-adjacent samples are full of experienced meditators. Familiar ground is not the same as solid ground.
Where we say plainly that claims run ahead of evidence. Leadership. The standard instrument is built for multi-rater assessment, and the validity of self-report on it is weak. We mark this one as the dimension with the widest gap between what is claimed and what has been shown. Worth noting that multi-rater assessment in a psychedelic context is not new. Ratings from people who knew the participants were used in the Hopkins studies and were consistent with the participants' own reports at 14 months. They were used again in the 2018 randomised study of 75 healthy participants, and in a double-blind trial during a five-day meditation retreat, where the pattern at four months was similar to the self-reports but less marked. We have not identified anyone who has done it for leadership. The hole is fillable.
Where self-report simply cannot carry the weight. Learning and memory. In a meta-analysis of 53 studies in normatively ageing adults, how well people judged their own memory barely tracked how well they actually performed. Task-based measurement or nothing.
To be exact about our own work: the twelve dimensions are the research focus. The first draft of our measurement instrument covers nine of them. Perception, learning and memory, and leadership are excluded from that draft and documented openly as open questions, each with a stated reason.
What the field has already built, and what is left
It would be easy, and wrong, to say that nobody is measuring any of this. Quite a lot has happened, and most of it in the last two years.
A 2024 review of 93 psychedelic trials found 17 different rating scales in use for the acute experience, and the authors called explicitly for a core outcome set and for instruments that also assess the setting. A 2025 systematic review from a different group, working on substance use disorder, closed with the same recommendation independently. Two research groups, two literatures, one conclusion.
The field has answered parts of that call. An international Delphi process involving 89 experts across 17 countries produced 30 extra-pharmacological variables for reporting setting, now published as the ReSPCT guidelines. Oregon's regulated psilocybin services are being tracked by a prospective cohort covering 24 of 26 licensed service centres, with 346 participants and 90.2% retention at three months. A senior coalition has called for well-being to become a primary endpoint in clinical trials.
Read that coalition paper closely, though, and it draws its own boundary twice, in its own words: "without implying approval for use in otherwise healthy populations," and approval and coverage "remain anchored to a diagnosed condition… rather than licensing treatment of its absence in otherwise healthy people."
They are being careful, and they are right to be. It also means the case Metanoia works on is one they have explicitly set aside.
The gap, stated precisely
Three tags, and all three have to be present or the claim is false.
Intention-referenced. The person states a purpose before exposure, and the outcome is assessed against that purpose rather than inferred afterwards. Without this tag the claim fails, because work on well-being endpoints is already moving.
Longitudinal to 365 days. Without this tag the claim fails, because twelve-month follow-up already exists in a running phase 1 trial in a clinical population, and the Oregon cohort already runs to three months.
In healthy adults. Without this tag the claim fails, because outcome measures for supervised services have already been defined by consensus.
Put together: we have not identified an agreed instrument, or an agreed set of reporting fields, for intention-referenced outcome measured longitudinally in healthy adults. The consequence is dull and serious. Use of that kind gets filed under a clinical indication it does not have, or it does not enter the record at all.
That is the gap we work in. The field is far from empty. Much of the record is being built by other people, and built well. The part we think we can build is the outcome measure for healthy adults.
One structural point about who can build it
A standard for measuring outcomes loses the thing that makes it a standard if it is written by people whose assets depend on the result. That is not an accusation against anyone. It is a condition for the independence of the record, and it narrows the field of possible conveners considerably. A neutral nonprofit that sells nothing to the people it informs is one of the few shapes that fits.
What we do not know
Whether deliberate, intention-referenced change in healthy adults is measurable at all with self-report instruments is an open question, and our own instrument could fail its validation. That would be a result, and we would publish it.
We have not identified a study that follows healthy adults who stated a purpose in advance out to a full year on fixed windows. Instruments for positive functioning certainly exist. The well-being paper cited above counts 99 generic well-being instruments, citing a 2016 review, and 196 proposed dimensions, and calls the field pre-consensus. What we have not identified is a validated instrument designed for intention-referenced change in healthy adults, one that assesses an outcome against a purpose the person stated before exposure.
And the finding most likely to be quoted against us is one we cite ourselves: in randomised trials in healthy adults, microdosing has not shown consistent benefit over placebo. The gap between the observational studies and the controlled ones is itself a research question, and a good one.
Sources
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1. Griffiths RR, Richards WA, Johnson MW, McCann UD, Jesse R. Mystical-type experiences occasioned by psilocybin mediate the attribution of personal meaning and spiritual significance 14 months later. J Psychopharmacol 2008;22(6):621–632.
PMID 18593735 · DOI · Level 1. 36 hallucinogen-naive adults. 64% said the experience increased well-being or life satisfaction, and 58% rated it among the five most meaningful experiences of their lives. Cited here as a demonstration of a measurement gap, never as evidence of benefit.
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2. MacLean KA, Johnson MW, Griffiths RR. Mystical experiences occasioned by the hallucinogen psilocybin lead to increases in the personality domain of openness. J Psychopharmacol 2011;25(11):1453–1461.
PMID 21956378 · DOI · Level 1. Openness rose after a high-dose session and remained above baseline more than a year later in those who had a mystical-type experience.
-
3. Kelly C, Cooley BJ, Zeng L, Hurzeler T, et al. Subacute and long-term changes in cognitive functioning after administration of classic psychedelics, MDMA and ketamine: a systematic review. Neurosci Biobehav Rev 2026;190:106911.
PMID 42600962 · DOI · Level 2. 67 studies. Quoted with the authors' own "may reflect" hedge intact.
-
4. Goldy SP, et al. Trip sitting or just sitting? Session facilitators substantially influence psychedelic experiences in clinical trials but not in healthy ones. Psychiatry Res 2026;359:117010.
PMID 41747432 · DOI · Level 1. About 0.8% of variance in healthy participants against about 13.6% in clinical ones.
-
5. Pokorny T, Preller KH, Kometer M, Dziobek I, Vollenweider FX. Effect of psilocybin on empathy and moral decision-making. Int J Neuropsychopharmacol 2017;20(9):747–757.
PMID 28637246 · DOI · Level 1. Double-blind, healthy volunteers. Emotional empathy increased, cognitive empathy did not, moral decision-making unchanged.
-
6. Kettner H, Gandy S, Haijen ECHM, Carhart-Harris RL. From egoism to ecoism: psychedelics increase nature relatedness in a state-mediated and context-dependent manner. Int J Environ Res Public Health 2019;16(24):5147.
PMID 31888300 · DOI · Level 1. Prospective online sample, N=654 at baseline, shifts at two weeks, four weeks and two years. Self-selected online sample, self-report, no control group, all stated in the article text.
-
7. Lyons T, Carhart-Harris RL. Increased nature relatedness and decreased authoritarian political views after psilocybin for treatment-resistant depression. J Psychopharmacol 2018;32(7):811–819.
PMID 29338538 · DOI · Level 1. n=7, open-label pilot, clinical population. Supports the "months" wording only.
-
8. Meshkat S, Leung M, Meshkat S, Lin Q, et al. Efficacy and safety of psychedelic microdosing on psychological outcomes in healthy adults: a systematic review and meta-analysis. CNS Drugs 2026;40(10):1369–1393.
PMID 42593636 · DOI · Level 1. 24 studies, 3,681 participants, healthy adults. RCTs: minimal impact on cognition, creativity or sustained mood.
-
9. Smigielski L, Kometer M, Scheidegger M, Krähenmann R, Huber T, Vollenweider FX. Characterization and prediction of acute and sustained response to psychedelic psilocybin in a mindfulness group retreat. Sci Rep 2019;9(1):14914.
PMID 31649304 · DOI · Level 1. Double-blind, n=39 meditators, five-day retreat, effects at four months corroborated by external ratings.
-
10. Baer RA, et al. Using self-report assessment methods to explore facets of mindfulness. Assessment 2006.
PMID 16443717 · Level 1. Factor structure of the five-facet instrument varies with meditation experience.
-
11. Crumley JJ, Stetler CA, Horhota M. Examining the relationship between subjective and objective memory performance in older adults: a meta-analysis. Psychol Aging 2014;29(2):250–263.
PMID 24955993 · DOI · Level 1. 53 studies. Samples are adults in normative ageing, so the generalisation to younger healthy adults is an inference and the article is worded to attribute the finding to the meta-analysis.
-
12. Hovmand OR, Poulsen ED, Arnfred S. Assessment of the acute subjective psychedelic experience: a review of patient-reported outcome measures. J Psychopharmacol 2024;38(1):19–32.
PMID 37969069 · DOI · Level 1. 93 trials, 17 rating scales, explicit call for a core outcome set and for instruments assessing setting.
-
13. Piper T, Small F, Brown S, Kelleher M, Mitcheson L, Rucker J, Young AH, Marsden J. Psychedelic-assisted treatment for substance use disorder: a narrative systematic review. Addiction 2025.
PMID 39887551 · DOI · Level 1. 37 studies. Closes with a call to "build consensus for a field-specific Core Outcome Set." A clinical-treatment review, described as such.
-
14. Pronovost-Morgan C, Greenway KT, Roseman L, et al. An international Delphi consensus for reporting of setting in psychedelic clinical trials. Nat Med 2025;31(7):2186–2195.
PMID 40461819 · DOI · Level 1. 89 experts, 17 countries, four rounds, 30 variables.
-
15. Korthuis PT, Cook RR, Gregoire D, Stauffer CS, et al. Safety and mental health outcomes of Oregon state-regulated psilocybin services. JAMA Netw Open 2026;9(8):e2630608.
PMID 42616497 · DOI · Level 1. OPEN cohort, n=346, 24 of 26 licensed service centres, 83 facilitators, 90.2% retention at three months. Presented as precedent and proof of feasibility, never as a competitor.
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16. Korthuis PT, et al. Core outcome measures for supervised psilocybin services: a three-stage e-Delphi. J Psychopharmacol 2024;38(8):761–768.
PMID 38888164 · Level 1. 36 experts, process, outcome and structure measures.
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17. Marseille E, Kettner H, Sgambati F, Kahn J, et al. Well-being as a primary endpoint. npj Ment Health Res 2026;5(1).
PMID 42581324 · DOI · Level 1. Described by the authors as a "pre-consensus phase." Both exclusion quotes above are verbatim from the full text.
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18. A randomized double-masked dose-controlled trial of psilocybin whole mushroom for obsessive-compulsive disorder. Sponsor Francisco A Moreno, University of Arizona, with the Arizona Biomedical Research Commission.
ClinicalTrials.gov NCT07347405 · Level 1. Phase 1, 30 participants, clinical population (OCD), monthly follow-up for 12 months after a 12-week treatment phase, recruiting. Supports the sentence that twelve-month follow-up exists in a running trial in a clinical population. No dose figure from the record is reproduced.
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19. Griffiths RR, Johnson MW, Richards WA, Richards BD, McCann U, Jesse R. Psilocybin occasioned mystical-type experiences: immediate and persisting dose-related effects. Psychopharmacology (Berl) 2011;218(4):649–665.
PMID 21674151 · DOI · Level 1. 18 adults, 17 hallucinogen-naive. Community observer ratings at 14 months were consistent with the participants' own reports. Doses deliberately not reported here. Full text consulted on 2 October 2026.
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20. Griffiths RR, Johnson MW, Richards WA, Richards BD, Jesse R, MacLean KA, Barrett FS, Cosimano MP, Klinedinst MA. 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 2018;32(1):49–69.
PMID 29020861 · DOI · NCT00802282 · Level 1. Double-blind, 75 healthy participants in three groups of 25, outcomes at six months including community observer ratings. Participants also undertook a programme of meditation and spiritual practice, and the authors note a homogeneous sample. Doses deliberately not reported here. Full text consulted on 2 October 2026.
Bibliographic source for all identifiers above: PubMed and ClinicalTrials.gov. Items 1, 2, 3, 5, 8, 12, 13, 14, 15 and 17 were re-verified directly against PubMed on 16 September 2026. The full texts of sources 2, 9, 17, 19 and 20 were consulted on 2 October 2026 for the statements about observer ratings and the instrument count.