This mixed‑methods study of 608 people reporting extended difficulties after psychedelic use found common problems—anxiety and fear, existential struggle, social disconnection and depersonalisation/derealisation—with about one third affected for over a year and one sixth for more than three years. Shorter duration was associated with knowing the dose and drug type and with lower acute difficulty, while a narrower range of difficulties was linked to taking the drug in a guided setting, with implications for harm reduction.
Long-term adverse experiences following psychedelic use can persist for weeks, months, or even years, and are relatively unexplored in psychedelic research. Our convergent mixed-method study gained quantitative and qualitative data from 608 participants who reported extended difficulties following psychedelic experiences. Data was gathered on the context of use, the nature and duration of the challenges they experienced (including a written description of these), plus a range of possible risk factors and perceived causes. The most common forms of extended difficulty were feelings of anxiety and fear, existential struggle, social disconnection, depersonalization and derealization. For approximately one-third of the participants, problems persisted for over a year, and for a sixth, they endured for more than three years. It was found that a shorter duration of difficulties was predicted by knowledge of dose, drug type and lower levels of difficulty reported during the psychoactive experience, while a narrower range of difficulties was predicted by taking the drug in a guided setting. Implications for psychedelic harm reduction are discussed.
Evans and colleagues situate their study within the recent ‘‘psychedelic renaissance’’, noting renewed clinical and public interest in substances such as psilocybin, LSD, ayahuasca and MDMA. While much contemporary research focuses on therapeutic benefits and on challenging acute ‘‘trip’’ experiences, the authors identify a gap concerning adverse experiences that persist well beyond the pharmacological effects. Earlier studies and surveys suggest such extended difficulties can include anxiety, perceptual changes, derealisation/depersonalisation and, in some cases, psychotic symptoms or long-lasting distress, but prevalence estimates, phenomenology and predictors remain poorly characterised. This study aims to describe the types, phenomenology and perceived causes of difficulties that last more than 24 hours after a psychedelic experience, and to test hypotheses about predictors of the range and duration of those difficulties. Using a convergent mixed-methods approach, the investigators collected quantitative checklist data and brief written narratives from people who reported enduring problems, with the goal of combining epidemiological description and inductive qualitative analysis to inform harm-reduction and future research priorities.
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The study used a convergent mixed-methods design in which quantitative and qualitative data were collected simultaneously via an anonymous online survey. Eligibility criteria were: having experienced difficulties after using a psychedelic that negatively affected functioning for more than one day, being aged 18 or over, and sufficient proficiency in written English. Recruitment occurred through social media, newsletters, student email lists and a newspaper advert; 608 individuals completed the survey between October 2022 and January 2023, and all provided written consent. The researchers report the sampling strategy as randomized sampling and state the sample provided satisfactory power for planned analyses. Ethical approval was obtained from the University of Greenwich. Quantitative data included closed-ended items on substance(s) used, setting (later grouped into guided versus unguided), whether dose was known, perceived duration and types of extended difficulties (emotional, self-perception, cognitive, social, ontological, spiritual, perceptual, other), and whether participants had prior or subsequent mental-health diagnoses or childhood trauma they believed relevant. Acute trip challengingness was measured by a single 4-point Likert item (Not at all to Extremely challenging). The ‘‘range of difficulties’’ variable was computed as the sum of selected difficulty categories. Statistical procedures were performed in IBM SPSS v.28, with significance adjusted to p = 0.02 using the Hochberg step-up method. Two linear regressions and one One-Way ANOVA were used to test predictors of range and duration of difficulties and differences by drug type; parametric assumptions are reported as met. For the qualitative component, the authors applied Structured Tabular Thematic Analysis (ST-TA), an inductive thematic method developed for brief-text datasets. Analysts proceeded through immersion, coding, tabulation, inter-analyst agreement checks, frequency exploration and thematic mapping. Two analysts independently coded subsamples until an agreement threshold of 80% was reached after three iterations. Three analysts (with backgrounds in philosophy/psychology, qualitative methods, and psychedelic research) conducted analysis within a dialogical, reflexive process including eight scheduled discussions to address potential biases and improve clarity of theme definitions. Participants were invited to write for about 3–5 minutes describing their lasting difficulties; 590 respondents supplied such narratives.
Sample and context: Among 608 respondents, the most commonly reported substances associated with enduring difficulties were psilocybin (27%) and LSD (25%), followed by ayahuasca (10%), cannabis (10%), MDMA (7%), DMT (5%), ketamine (4%), mescaline (2%) and salvia divinorum (1%); 8% selected Other and specified compounds including iboga, 5‑MeO‑DMT and bufo. Regarding dose knowledge, 449 (73.8%) said they or someone present knew the dose, 156 (25.7%) said no. The most frequent locations for the index experience were ‘‘with a friend, partner or group of friends’’, then ‘‘on my own’’, and ‘‘in a group ceremony’’. Settings were later grouped into guided versus unguided for analyses. Duration and types of extended difficulties (closed-ended): Responses to duration categories showed prominent peaks at 1–3 years and >3 years, indicating many participants reported very long-lasting problems. On the closed-ended checklist, emotional difficulties were the most endorsed type (76%), followed by self-perception difficulties (58%) and cognitive difficulties (52%); 50% reported ontological difficulties and 34% reported spiritual difficulties. Mental-health and trauma correlates, and attitudes: Prior to the experience, 173 (28.5%) reported a mental-health diagnosis; among these, 79 (45.9%) thought that prior diagnosis may be linked to the post-psychedelic difficulties. Childhood or youth trauma that participants regarded as potentially contributory was reported by 243 (40%). After the psychedelic experience, 114 (18.8%) reported receiving a subsequent mental-health diagnosis; of those, 59 (53.6%) believed the psychedelic experience had contributed. Regarding ongoing use and attitudes, 334 (54.9%) reported they still take psychedelics, 246 (40.5%) said they do not; 89.7% agreed or strongly agreed that insights gained from psychedelics in supportive settings are worth the risks. Predictors of range and duration: A linear regression predicting range of difficulties (N around 524) yielded a significant overall model (R2 = .04, F(4,519) = 4.97, p < .001). Two predictors reached significance: greater acute challengingness of the trip (β = .17, p < .001) and being in an unguided setting (β = .11, p = 0.008). A separate regression predicting duration produced a significant model (R2 = .06, F(4,518) = 7.73, p < .001) in which only trip challengingness was a significant predictor (β = .21, p < .001); being in an uncontrolled setting and not knowing dose trended in the predicted direction but were not significant. Drug differences: After excluding polysubstance reports and very small groups, One-Way ANOVAs tested drug effects. Drug type significantly affected duration (F(9,477) = 2.89, p = 0.002) but not range (F(9,480) = 1.33, p = 0.06). Post-hoc LSD comparisons indicated longer durations principally associated with ayahuasca, DMT and LSD, whereas psilocybin and MDMA were associated with shorter durations. Qualitative thematic findings: From 590 written narratives, the inductive ST-TA produced a large thematic scheme. Principal meta-themes and selected prevalence figures reported in the extracted text include Emotional Difficulties (67% of narratives), Existential and Ontological Difficulties (42%), Self‑Perception Difficulties (including depersonalisation at 16%), Somatic Difficulties (19% with sleep problems at 9%), Cognitive Difficulties (18% overall, with confusion in 9%), Behavioural Difficulties (substance-use problems 2%, work/study/financial impairment 5%) and discrete reports of psychotic episodes. Within emotional themes, anxiety/fear was the most common sub-theme (26%), followed by paranoia (11%), panic attacks (9%), depression (12%) and suicidality (6%). Perceptual disturbances and visual distortions (including reports coded as flashbacks and HPPD-like symptoms) were also described; the analysts distinguished flashbacks from prolonged perceptual symptoms when participants used those terms. Many narratives described resurfaced trauma, existential struggle, derealisation and fear of permanent damage. The authors present exemplar quotations to illustrate each sub-theme and note heterogeneity in phenomenology, intensity and duration of reported difficulties.
Evans and colleagues interpret their convergent findings as indicating that extended difficulties after psychedelic use are heterogenous but commonly emotional in nature, with anxiety, fear and panic prominent across both checklist and narrative data. The quantitative checklist found emotional problems most commonly (76%), and the inductive narratives corroborated this with emotional themes appearing in 67% of written accounts; other frequent problem domains included self‑perception changes, cognitive impairment, existential/ontological disturbance and perceptual anomalies. The authors emphasise that extended difficulties vary substantially in duration, with many participants reporting problems that last over a year. In relation to prior literature, the study’s results align with earlier surveys that highlight anxiety and social disconnection as common post-psychedelic difficulties, and they complement case reports and smaller qualitative studies documenting derealisation, depersonalisation and persistent perceptual changes. The finding that acute trip challengingness predicts both a broader range and longer duration of subsequent difficulties supports previous recommendations to limit the duration of acute distress. Likewise, identification of unguided settings as associated with a greater range of difficulties accords with literature emphasising preparation, dose knowledge and guided support as protective factors. Drug-specific differences were observed, with ayahuasca, DMT and LSD linked to longer-lasting problems than psilocybin or MDMA in this sample. The authors acknowledge several limitations that constrain inference. The sample was self-selected, mainly Western, English-speaking and predominantly white, limiting generalisability across cultures or contexts where psychedelics are ritualised. Data are cross‑sectional and based on retrospective self-report, so recall bias and subjective attributions affect the findings and causal claims cannot be made. The written narratives were brief by design, precluding in-depth probing; the authors note that follow-up interview studies are planned to explore themes such as childhood trauma and existential struggle more thoroughly. Methodological challenges in thematic coding are also acknowledged: the team conducted three iterations to reach an 80% inter-analyst agreement and suggest future work might consider a more streamlined coding frame for replicability. Practically, the investigators argue their findings have implications for harm reduction, informed consent and integration support. Given the prominence of anxiety and fear among enduring difficulties, they recommend that legal providers and clinical trial teams supply clear guidance on self-soothing and coping strategies, inform participants about the range and possible duration of adverse outcomes, and offer integration resources over months where needed. The authors also highlight the complexity that some difficult experiences are later appraised as meaningful or growth-promoting by participants, which complicates binary ‘‘adverse versus beneficial’’ classifications and suggests the importance of individual appraisal and integration support. Finally, they call for further research into specific phenomena identified here—such as derealisation, long-term perceptual disturbances, social disconnection and harms arising within guided settings—to better characterise risks and protective practices.
Ethical approval for the study from the University of Greenwich was gained prior to data collection commencing (application ref:. Data was collected anonymously via an online survey created in the online survey platform Qualtrics, between November 2022 and April 2023. The questionnaire comprised a written consent form, followed by a series of open-ended and closed-ended questions. Closed-ended questions about extended difficulties and interpretations of these are described in the Results section. Similar to Simonsson et al., we measured how challenging the acute psychedelic experience was by way of a single item "How challenging was the psychedelic experience itself", with a 4-point Likert scale response: Not at all challenging, Moderately challenging, Very challenging, Extremely challenging. The variable: "Range of difficulties experienced" was calculated as the sum of difficulty types reported via the closed-ended question reported in Table, in which participants were presented with a set of extended difficulty categories (emotional, self-perception, cognitive, social, ontological, spiritual, perceptual, other) and ask to select all those that apply. In terms of qualitative data collection, the instruction provided to participants to describe the difficulties they experienced in written form, was as follows: "Please describe the lasting difficulties that you encountered after your psychedelic experience. We would like you to write for about 3 to 5 minutes." Participants were provided with a debrief form at the end of the questionnaire, which provided information about support organizations and information websites that help with psychedelic harm reduction and the integration process.
The aim of this study was to investigate the enduring adverse experiences following the use of psychedelic drugs. We looked at the phenomenology, perceived etiology, relationship to risk factors, and relationship to continued usage/attitudes to psychedelics of such difficulties. Our first quantitative research question looked at the prevalence of types of these difficulties. When provided with a fixed checklist of emotional, self-perception, cognitive, social, ontological, spiritual and perceptual difficulties, emotional difficulties emerged as the most prevalent, and perceptual difficulties as the least prevalent. The qualitative research question looked at the nature of the difficulties within the brief written narratives. When describing their difficulties in this way, and with coding these inductively into meta-themes and subthemes, the most prevalent meta-theme was Emotional Difficulties, supporting the quantitative checklist, with "Anxiety, fear and worry (non-specific)" being the most prevalent subtheme, with a suite of other subthemes that also relate to fear and anxiety, such as paranoia, panic attacks, fear of death, feelings of being unsafe, hypervigilance and phobias. In summary, what stands out from both quantitative and qualitative analysis is that emotional difficulties are the most common form of enduring difficulties, and these most commonly take the form of anxiety, fear and panic. We discuss implications of this towards the end of this section. A further conclusion that emerges from the quantitative and qualitative findings together is that extended difficulties are highly heterogenous in duration, intensity and phenomenology, and this internal differentiation requires targeted studies to better understanding, for example, difficulties that last more than a year or specific kinds of challenges such as ontological difficulties. Our findings supports the results of Simonsson et al., who found that anxiety was the most common enduring difficulty, based on quantitative questionnaire dataand Bouso et al's study of the Global Ayahuasca Survey, in which 'feeling nervous, anxious or on edge' was the second most common adverse mental health effect. Our findings also suggest that a Sense of disconnection from others was within the top five most prevalent themes, as did the studies by Simonsson et al.and Bouso et al.. Some extended adverse effects that were quite common in other studies weren't so common in our data set-for example, feeling a harmful connection to the spirit world was reported by 14% of respondents to the Global Ayahuasca Survey but by less than 4% of our data set, which may suggest some forms of difficulty are particularly associated with certain psychedelic substances and/or their associated cultures. The second quantitative research question asked what contextual social settings and psychedelic substances precede extended difficulties. The most common social contexts for the psychedelic experiences that preceded the extended difficulties were 'with a friend, partner, or group of friends' or 'on my own'. When comparing social settings in this dataset (which is of course exclusively from individuals who reported extended difficulties), to social settings reported in a sample of general psychedelic usage, 12% of the current sample reported taking it at a party or similar event, but only 3% did in the comparison sample of all users, and while 18.9% our of our sample reported taking in in solitude, 43% of the general sample did. This suggests an avenue for future enquiry could be in looking at specific social contexts as risk factors for extended difficulties. 8% of our respondents experienced extended difficulties after taking part in a clinical trial or psychedelic therapy session. Thus, our data suggests that taking psychedelics in a clinical setting is not risk-free.The psychedelics most frequently mentioned as preceding extended difficulties were psilocybin and LSD, however this may simply reflect higher prevalence use. Ayahuasca, DMT and LSD were associated with the longest average duration of difficulty. Carbonaro and colleagues' previous research suggested the duration of the difficult experience was predictive of adverse outcomes and they recommend that therapeutic interventions aim at reducing the duration of the challenge. In the current study, 40% of the sample stated that they thought a childhood trauma was implicated in experiencing the post-psychedelic difficulties. This has similar theoretical connotations to the Simonsson et al. finding that a major life event prior to the experience was predictive of degree of enduring difficulty, in terms of antecedent life events being formative to psychedelic outcomes. Previous research has identified a strong link between childhood trauma and developing dissociative symptoms following classic psychedelic useas well as increased vulnerability to the development of psychiatric disorders. Our third quantitative descriptive research questions focused on the extent to which participants attribute a relationship between enduring difficulties and (a) childhood traumatic experiences, or (b) prior or subsequent diagnoses of mental illness. These questions were answered, with figures for both being just under half of participants. We will be investigating these perceived etiological links within interview-focused studies in subsequent studies. Our fourth quantitative research question looked at current attitudes towards and usage of psychedelics among this sample of individuals who have previously encountered difficulties related to psychedelic. The majority reported continued usage, and almost 90% report a positive view on the therapeutic benefits of psychedelics. This may point to the formative role of difficult experiences within the integration process. Bathje et al. state that overcoming difficulties may actually catalyze the integration process for some individuals. There is also empirical evidence that trips involving major personality changes like the overcoming of addiction or the confrontation with repressed trauma are, unsurprisingly, challenging but nonetheless ultimately experienced as healing. Whether a phenomenon is experienced as 'bad' or 'part of the process' depends on a person's appraisal. As with meditation experiences, emergent phenomena like depersonalization could be appraised as expected and welcome by some individuals, while others may find them unexpected and unsettling. Indeed, the same person might appraise such phenomena differently at different life stages. Some individuals might intentionally use psychedelics as a tool to revisit traumatic memories, while others in our survey reported feeling overwhelmed by the resurfacing of traumatic experiences. As previous work has cautioned, re-triggering trauma with psychedelics can augment maladaptive processes and associated defense mechanisms, especially in individuals with increased vulnerability due to childhood trauma. Previous research supports the notion that challenging extended psychedelic experiences are not necessarily adverse outcomes. In Simonsson's 2023 study, 78.6% of participants reported they were glad they had used psychedelics, after reflecting on their most difficult experiences. A third of the participants interviewed by Bremler et al. attributed personal growth to the difficulties triggered by their psychedelic experience. Gashi et al. also previously showed that 'bad trips' can be narratively transformed into valuable experiences. 84% in Carbonaro's study reported they benefited from their challenging trip even when it was one of the most difficult experiences of their lives. Related to this, the same study found the degree of difficulty of an experience correlated positively with the degree of personal meaning gained from the experience. Also, 67% participants in the Johnstad (2021) study reported long-term consequences of their worst psychedelic experience to be positive, while only 4% reported negative consequences. Bouso et al. found that 55% of respondents to the Global Ayahuasca Survey reported adverse mental health effects, but 88% thought such effects were 'part of a positive process of growth or integration'. In the 2022 Canadian Psychedelic Survey, 56% of those who had an intense challenging experience reported that 'some good' came from the experience. Providing some support for these previous findings, in the current study, 55% continue to take psychedelics to the present day, and 90% agreed that psychedelics can be helpful and are worth the risks if taken in supportive settings. Nonetheless, almost half no longer take psychedelic drugs, and in some instances, respondents reported feeling significantly harmed by their psychedelic experience and expressed regret over ever trying these substances. In terms of the hypotheses that were tested, these were partially supported. Experiencing a greater range of difficulties was predicted by being in an unguided setting at the time of the trip and having a more challenging trip. Duration of difficulties was predicted by the challengingness of the trip but no other factors emerged as significant. We also found that difficulties following the use of ayahuasca, DMT and LSD were longer than other drugs. A prior diagnosis of mental illness did not predict the duration or variety of enduring difficulties. This supports the findings from Simonsson et al. that a high dose (which is likely in the absence of clear knowledge of dose) and a disagreeable physical environment were predictive of degree of difficulty.
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