Extended difficulties after psychedelic experiences: Prevalence and associations in a global, multilingual sample

As psychedelic use moves closer to mainstream medicine, the authors note growing concern about adverse reactions and long-lasting difficulties that can follow psychedelic experiences. Earlier studies had suggested that a minority of users experience persistent psychological or perceptual problems, but most evidence came from single-country samples and the overall prevalence, characteristics, and correlates of these extended difficulties remained poorly characterised in a large international setting. The introduction also highlights that prior findings vary widely, with some studies reporting low rates of lasting impairment and others finding more substantial levels of anxiety, depression, social disconnection, reactivation of effects, craving, and broader distress. Oliver and colleagues set out to use data from the Global Psychedelic Survey (GPS) 2025 to estimate how common extended difficulties are, describe the kinds of difficulties reported and how long they last, and examine what demographic, personality, psychedelic-use, and social-support factors are associated with clinically relevant difficulties. Their specific focus was on difficulties lasting at least a month and interfering with daily life, in order to better understand who may be at higher risk and what the broader context of these experiences may be.

This study analysed data from the GPS 2025, an international multilingual online survey led by researchers at the Michigan Psychedelic Center with collaborators from more than 20 countries. The survey was reviewed by the University of Michigan institutional review board and judged exempt from ongoing review. It was delivered in English and 18 other languages, with translation and back-translation used for non-English versions. Recruitment took place through newsletter articles, social media, traditional press interviews, collaborator channels, NGO mailing lists, and some paid Meta advertising. The total survey sample was 9,087, and 6,476 participants completed the extended-difficulties section used in this paper. Participants came from 120 countries; just under half were female at birth and just over half were male at birth. The paper reports educational and employment distributions, but not a detailed clinical sample because this was a broad naturalistic survey of people who had used psychedelics. Participants were asked whether they had experienced a range of harms or difficulties lasting more than 24 hours after the acute psychedelic effects had subsided, and they could indicate duration bands from less than one week to more than one year. For the analysis of clinically relevant difficulties, the researchers created a binary variable indicating both a difficulty lasting more than one month and a mean rating of at least 2 on disruption to daily life across the 11 difficulty types. They used t-tests and chi-square tests to examine associations with demographic, personality, psychedelic-use, and social-support variables, reporting Cohen’s d and Cramer's V as effect sizes alongside p values. Analyses were run in SPSS version 29.

Among the 6,476 respondents who completed this section, 48.3% reported at least one difficulty lasting 24 hours or more after psychedelic effects had subsided. The proportion declined with longer duration: 40.8% reported difficulties lasting 24 hours to one week, 31.6% reported difficulties lasting more than one week to less than one month, 18.5% reported difficulties lasting more than one month to less than one year, and 9.9% reported difficulties lasting more than one year. The most commonly reported difficulties were existential struggle (36.6%), feelings of depression (34%), and derealisation (29.4%). Existential struggle was the most common difficulty across three of the four duration bands, while depression was the most common for the 24 hours to one week band. Existential struggle was also rated as the most severe difficulty and as the one most likely to contribute to healing. Lowered self-esteem was the difficulty most associated with interference in daily tasks. The paper reports that all difficulty types were endorsed across the five inhabited continents, with only very small continental differences overall. The main variation was for existential struggle, which was relatively high in Asia (53.9%), and depressed feelings, which were relatively low in Oceania (25.8%), but the effect sizes were weak. Clinically relevant disruptive difficulties, defined as lasting at least a month and negatively affecting daily life, were reported by 8% of the sample who completed the section, corresponding to 547 of 6,746 as written in the extracted text. Within this group, 42.4% sought external support to help manage the difficulties and 79.1% said that support was effective. By comparison, 27% of other participants sought external support and 93.6% of those found it effective. The authors also report that people with clinically relevant difficulties were more likely to link their difficulties to specific drugs and settings, although the extracted text does not provide all of the table values in full. The variables associated with clinically relevant disruptive difficulties were consistent across several domains. Those affected were younger at the time of survey and younger when they first used psychedelics, had lower income, were more likely to be single, and reported less family approval of psychedelics. They also had lower conscientiousness, lower agreeableness, and lower emotional stability, alongside higher anxiety and depression symptoms. They were more likely to be using psychedelics to treat a mental health condition or problematic behaviour, reported higher severity and disruption of their difficulties, and were less supportive of legal access to psychedelics. MDMA was the only drug that respondents did not specifically endorse as being associated with extended difficulties.

The authors interpret the findings as showing that extended post-psychedelic difficulties are both common and varied in this global survey, although only a minority reported difficulties that were clinically disruptive and long lasting. They emphasise that almost half of respondents experienced some difficulty lasting longer than 24 hours, and that 9.9% reported difficulties lasting more than a year. In their view, the profile most strongly associated with clinically relevant difficulties included lower emotional stability, higher anxiety and depression, greater severity and disruption, and a greater likelihood of seeking support. Oliver and colleagues compare their prevalence estimates with earlier surveys and note that their rates are higher than some studies measuring short-term functional impairment, but closer to other naturalistic reports of prolonged adverse effects. They suggest that differences between studies may reflect variations in sample composition and question wording. They also note that MDMA was the only substance not clearly linked by respondents to extended difficulties, and cautiously raise the possibility that MDMA may carry a lower odds of very long and disruptive adverse effects, while stressing that this is preliminary. The discussion highlights existential struggle as a particularly important theme: it was the most common long-term difficulty, especially in Asia, and the most severe, but it was also seen as the strongest contributor to healing. The authors connect this to earlier interview-based work suggesting that existential distress can support meaning-making and transformation, and to previous surveys in which many respondents still judged benefits to outweigh risks in supportive environments. The paper also places emphasis on risk factors and context. Younger age at first use, lower emotional stability, pre-existing mental health problems, using psychedelics to self-treat depression or anxiety, low family support, and negative or uncontained settings were all discussed as markers of greater vulnerability. The authors suggest these findings reinforce the need for screening and safety guidance, particularly for people with major depressive disorder or generalised anxiety disorder, though they acknowledge that the association may also reflect greater baseline distress rather than direct causation by psychedelics. The stated limitations are important. The study is retrospective and therefore vulnerable to recall bias. The sample was self-selected and likely over-represents people with strong experiences and more psychedelic-literate or pro-legalisation views. The multilingual design is a strength, but the authors note that some translation steps relied partly on Google Translate before expert review, which may have affected nuance. They also stress that the study is correlational and cannot determine whether psychedelics caused the difficulties or worsened pre-existing problems. They argue that future prospective longitudinal research is needed, including work on why existential struggle appears both highly distressing and potentially healing, and on what forms of support are most effective for people with extended difficulties.

The authors conclude that, in a large and globally diverse survey, extended post-psychedelic difficulties were heterogeneous and clinically meaningful for a substantial minority of participants. They state that although many people experience transient challenges that are understood as part of a longer healing process, approximately 6% experienced difficulties with clinically significant disruption lasting more than a month, and this group appears to warrant further attention in research and support services.