Personality & Trait Factors

This report summarises what Blossom’s database shows about psychedelics and personality. It is worth being clear what kind of page this is. It is not a condition page and not a treatment. It is about a famous idea, that psychedelics can change personality, and a quieter one, that personality shapes the response, and about how much weight the evidence can actually bear. The short answer is that the famous idea is more myth than the field admits, and the quiet idea is the steadier one.

A note before the evidence

This page is a research summary, not medical advice, and nothing here is a recommendation to take psychedelics. It is also worth a specific caution: claims that a single experience will durably improve your personality are exactly the kind of appealing, hard-to-test promise that this literature does not support. Read the evidence below as a corrective to that promise, not an endorsement of it.

The famous claim, and why it is shaky

The headline is that psychedelics durably increase "openness to experience", one of the Big Five personality traits. It is repeated everywhere, and it is weaker than it sounds. The most revealing evidence is a head-to-head trial: in psilocybin versus escitalopram for depression, openness rose under both, with no significant difference between the psychedelic and the ordinary antidepressant, and the change was not shown to persist to six months[1]Psychol Med (2023), psilocybin vs escitalopram: openness rose under BOTH with no between-condition difference; only neuroticism and disagreeableness stayed down at 6 months. If a standard antidepressant moves "openness" just as much, the trait shift is not a special property of the psychedelic experience.

There is a genuine controlled signal, but it points elsewhere. A psilocybin trial in alcohol use disorder found reduced neuroticism and increased extraversion and openness against placebo[2]Am J Psychiatry (2025), psilocybin-AUD RCT (n=84): vs placebo, reduced neuroticism and increased extraversion and openness at week 36 (secondary analysis), and a healthy-volunteer study found reduced neuroticism a month after a high dose[3]Neuroscience Applied (2025), healthy-volunteer psilocybin (25 vs 1 mg): the durable trait that moved was reduced neuroticism at one month, moderated by experience meaningfulness. Notice the pattern: the trait that moves most reliably is neuroticism, downward. And reduced neuroticism is very hard to separate from simply being less depressed and anxious, which is to say it may be symptom relief showing up on a personality scale, not personality change as such.

The numbers that look biggest are not change at all

The most dramatic "openness" figures come from a different kind of study entirely. A large cross-sectional survey found a very large openness difference (d=1.72) between people who use psychedelics and people who do not[4]Scientific Reports (2024), cross-sectional Swedish survey: users vs non-users differ on openness (d=1.72) — self-selection, not change (n=400 vs 400). That sounds like overwhelming evidence until you notice it is not a before-and-after at all: it compares two different groups of people at one moment. The straightforward explanation is self-selection, open, curious, experience-seeking people are more likely to take psychedelics in the first place. The drug did not necessarily make them open; their openness helped lead them to the drug.

This is the single most common error in the personality story, and it is worth stating plainly: a difference between users and non-users is not evidence that the drug changed anyone. The honest, within-person, controlled evidence is far more modest than the cross-sectional gap implies, and the broadest synthesis of it, a meta-analysis of ten studies and 304 participants, found no significant effect on the majority of personality and related measures[5]Neurosci Biobehav Rev (2024), meta-analysis (10 studies, 304 participants): no significant effects on the majority of personality, cognition and emotional-processing measures. That null result is the proper baseline against which every exciting individual finding should be read.

Personality as a predictor: the steadier story

There is a version of this topic that holds up better, and it is the one that gets less attention. Rather than asking whether psychedelics change personality, it asks whether personality predicts the experience and the response. Here the evidence is steadier. Traits like absorption and suggestibility appear to forecast outcomes: pre-treatment suggestibility predicted response to psilocybin (but not to escitalopram)[6]Psychol Med (2024), expectancy for psilocybin did NOT predict response; pre-treatment trait suggestibility predicted psilocybin (not escitalopram) response (n=55), and personality measurably shapes the sensory character of the experience[7]Drug Alcohol Rev (2026), personality predicts the sensory effects of psychedelics (personality-as-predictor of the acute experience) and predicts features of the LSD state[8]Transl Psychiatry (2024), pharmacological and personality predictors of the LSD experience in healthy volunteers (meta-analysis). This is more useful and more defensible than the trait-change claim, because it does not require personality to do the one thing personality is defined not to do, change easily.

Interestingly, the same work complicates the lazy "it is all expectancy" dismissal. In one trial, expectancy for psilocybin did not predict the response to psilocybin[6]Psychol Med (2024), expectancy for psilocybin did NOT predict response; pre-treatment trait suggestibility predicted psilocybin (not escitalopram) response (n=55), so the changes are not simply a matter of believing the drug will work. The picture is subtler than either "psychedelics transform personality" or "it is all placebo": specific traits predict specific responses, in ways that are starting to be mapped, even as durable trait change remains unproven.

Why "personality change" is an extraordinary claim

It helps to remember what personality is. By definition, traits are the relatively stable, enduring patterns that persist across situations and years, which is exactly why "a single dose durably changed my personality" demands strong evidence. The field has small samples, self-report questionnaires administered over weeks rather than years, few long follow-ups, and effects that are often non-specific or null. The naturalistic reports of lasting change, such as ayahuasca cohorts describing durable personality and quality-of-life shifts[9]Psyche (2026), naturalistic ayahuasca/Shipibo cohort: self-reported lasting changes in personality and quality of life (uncontrolled, traditional setting), are uncontrolled and self-selected, and the survey work on perceived personality change[10]J Psychedelic Studies (2023), survey of perceived psychedelic personality change and its moderators (self-reported belief about change) measures belief about change, not change itself.

None of this means nothing happens. People plainly have experiences they describe as changing them, and in patients some trait scores do move under controlled conditions. The defensible claim is narrow: that easing an illness can shift some trait measures, mostly neuroticism downward, in ways that may reflect symptom relief and may or may not last. The grand claim, that psychedelics reliably and durably rewrite healthy personality, is not something this evidence establishes.

Reading this honestly

So how should you read the personality story? As a famous claim that needs deflating, paired with a quieter one worth taking seriously. The deflation: "psychedelics durably increase openness" rests on small samples, short follow-ups, effects no larger than a standard antidepressant, cross-sectional comparisons mistaken for change, and a broad meta-analysis that is mostly null. The trait that actually moves in controlled work is neuroticism, downward, and that is hard to distinguish from feeling better. The quieter, sturdier story is that personality predicts the experience and the response, which is both more defensible and more clinically useful. The most valuable thing this literature offers an honest reader is the discipline to ask, every time someone says a psychedelic changed who they are, a simple question: changed compared to what, measured how, and for how long? The answers, so far, are more modest than the myth.