Which personality traits change, and by how much?
The most consistent finding across studies is that psychedelic-assisted therapy reduces neuroticism—the tendency toward anxiety, moodiness, and emotional reactivity. In the largest and most rigorous trial here, a 2025 double-blind, placebo-controlled study of 84 adults with alcohol use disorder, those who received psilocybin therapy showed significantly greater reductions in neuroticism than the placebo group, along with increases in extraversion (sociability, assertiveness) and openness (imagination, appreciation for art and feelings) [1]. The changes were driven by specific facets: depression, impulsiveness, and vulnerability dropped, while openness to feelings and fantasy rose.
A 2024 study in 60 healthy, psychedelic-naïve volunteers found that a single 25 mg dose of psilocybin reduced neuroticism one month later, with effect sizes large enough to be clinically meaningful [6]. This study also showed that the reduction was moderated by how meaningful and psychologically insightful the acute experience was—meaning the subjective quality of the trip matters.
A 2024 survey comparing 400 Swedish psychedelic users to 400 matched non-users found that users had lower depression scores, and this difference was explained by lower neuroticism [4]. Users also scored much higher on openness (a very large effect size of 1.72), suggesting that personality differences may both predispose people to try psychedelics and be amplified by them.
How does the therapy produce these changes?
The personality changes don't happen from the drug alone—they depend on the psychological support and the nature of the experience. In the 2025 trial, participants received 12 weekly psychotherapy sessions alongside the medication, and the changes were durable through 36 weeks of follow-up [1]. The 2024 healthy-volunteer study found that reductions in neuroticism were linked to the subjective meaningfulness of the experience and to a specific measure called 'dread of ego dissolution'—a challenging but potentially transformative state [6].
Surveys of psychedelic practitioners (40 providers who oversaw over 1,600 sessions) reveal that challenges like intense dysphoria (42% of providers reported this) and re-engaging with trauma (17%) are common, and 70% felt that people with PTSD or prior trauma need extra psychological support [3]. This underscores that the therapy context—trust, emotional safety, and skilled facilitation—is critical for positive personality change.
The EMBARK therapy framework, a comprehensive guide for clinicians, emphasizes that ethical, trauma-informed, and culturally competent care is foundational to effective psychedelic therapy [8]. This aligns with the practitioner survey finding that most providers prefer an 'emotive' approach (emphasizing human connection and spirituality) over a purely biological one [2].
What are the limits and risks?
Not everyone responds the same way, and the evidence is still emerging. The 2025 trial was in people with alcohol use disorder, so results may not generalize to healthy individuals or other conditions [1]. The 2024 healthy-volunteer study used a within-subjects design (not a randomized control), which can overestimate effects [6].
Personality changes can also be negative if the experience is poorly managed. Practitioners report that intense dysphoria and disappointment with the intervention are common challenges [3]. People with personality disorders are often excluded from trials, so we don't know how safe or effective this is for them—though a 2025 review suggests psychedelic therapy might help by targeting core personality pathology [7].
Importantly, a 2021 study showed that personality can also be changed through a digital intervention (a smartphone app) without any drugs, with self-reported changes of d=0.52 for increasing a trait and d=-0.58 for decreasing one [5]. This means psychedelics are not the only path to personality change, and the therapy component may be as important as the drug.
About These Sources
This answer is built on 8 peer-reviewed studies — published from 2021 to 2025, 7 from 2024 or later, 4 in Q1 journals, collectively cited 279 times — selected as the most relevant from 9 studies that passed quality screening, drawn from 70 papers retrieved from a database of over 500 million.
Sources used in this answer
Multidimensional Personality Changes Following Psilocybin-Assisted Therapy in Patients With Alcohol Use Disorder: Results From a Double-Blind, Placebo-Controlled Clinical Trial
In a double-blind, placebo-controlled trial of 84 adults with alcohol use disorder, psilocybin-assisted therapy significantly reduced neuroticism and increased extraversion and openness compared to placebo, with reductions in impulsiveness linked to lower drinking.
Psychological Support Approaches in Psychedelic Therapy
A survey of 40 psychedelic practitioners found a slight preference for an 'emotive' approach (emphasizing human and spiritual elements) over a neuromodulatory one, with training at certain institutions increasing this preference.
Provider perspectives on challenges in treatment during psychedelic therapy
A survey of 40 providers who oversaw 1,656 psychedelic sessions identified intense dysphoria (42% of respondents), disappointment (25%), and trauma re-engagement (17%) as common challenges; 70% felt PTSD patients need extra support.
Personality traits explain the relationship between psychedelic use and less depression in a comparative study
A comparison of 400 Swedish psychedelic users vs. 400 matched non-users found users had less depression (d=-0.29) and higher openness (d=1.72), with lower neuroticism explaining the depression difference.
Changing personality traits with the help of a digital personality change intervention
A randomized controlled trial of 1,523 participants using a smartphone app (PEACH) showed that personality traits can be changed through a 3-month digital intervention, with self-reported changes of d=0.52 (increase) and d=-0.58 (decrease), persisting 3 months later.
An investigation of acute physiological and psychological moderators of psychedelic-induced personality change among healthy volunteers
In 60 healthy volunteers, a single 25 mg dose of psilocybin reduced neuroticism one month later, moderated by the subjective meaningfulness of the experience and dread of ego dissolution.
Exploring serotonergic psychedelics as a treatment for personality disorders.
A review argues that psychedelic therapy may treat personality disorders by promoting adaptive personality changes, but notes that rigorous research is lacking and individuals with PDs are often excluded from trials.
EMBARK Psychedelic Therapy for Depression
The EMBARK framework for psychedelic therapy outlines a transdiagnostic, ethical approach with four cornerstones of care (trauma-informed, culturally competent, ethically rigorous, collective care) and six clinical domains.