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The Challenging Experience Questionnaire: Characterization of challenging experiences with psilocybin mushrooms
Open accessAbstract
Acute adverse psychological reactions to classic hallucinogens ("bad trips" or "challenging experiences"), while usually benign with proper screening, preparation, and support in controlled settings, remain a safety concern in uncontrolled settings (such as illicit use contexts). Anecdotal and case reports suggest potential adverse acute symptoms including affective (panic, depressed mood), cognitive (confusion, feelings of losing sanity), and somatic (nausea, heart palpitation) symptoms. Responses to items from several hallucinogen-sensitive questionnaires (Hallucinogen Rating Scale, the States of Consciousness Questionnaire, and the Five-Dimensional Altered States of Consciousness questionnaire) in an Internet survey of challenging experiences with the classic hallucinogen psilocybin were used to construct and validate a Challenging Experience Questionnaire. The stand-alone Challenging Experience Questionnaire was then validated in a separate sample. Seven Challenging Experience Questionnaire factors (grief, fear, death, insanity, isolation, physical distress, and paranoia) provide a phenomenological profile of challenging aspects of experiences with psilocybin. Factor scores were associated with difficulty, meaningfulness, spiritual significance, and change in well-being attributed to the challenging experiences. The factor structure did not differ based on gender or prior struggle with anxiety or depression. The Challenging Experience Questionnaire provides a basis for future investigation of predictors and outcomes of challenging experiences with classic hallucinogens.
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“Barrett et al. (2016) created the Challenging Experience Questionnaire (CEQ), which is designed to quantify challenging experiences under the influence of psychedelics (Barrett et al., 2016).”
From Assessment of the acute subjective psychedelic experience: A review of patient-reported outcome measures in clinical research on classical psychedelics (2024) · cites this paper as Barrett et al., 2016
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“The CEQ comprised of 26 items, each rated on a six-point Likert scale. Seven factors are assessed, including grief, fear, death, insanity, isolation, physical distress, and paranoia, to provide a phenomenological profile of challenging aspects of experiences with a classical psychedelic.”
From Assessment of the acute subjective psychedelic experience: A review of patient-reported outcome measures in clinical research on classical psychedelics (2024) · cites this paper as Barrett et al., 2016
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Sorted by citations
Items 101–200 of 324
Psychedelic drugs and perception: a narrative review of the first era of research
Aday, J. S., Wood, J. R., Bloesch, E. K., & Davoli, C. C. (2021) · Reviews in the Neurosciences · doi:10.1515/revneuro-2020-0094 · Cited by 55
“…to, alterations in sense of self (Lebedev et al. 2015), emotional breakthroughs (Roseman et al. 2019), psychologically challenging experiences (Barrett et al. 2016), and mystical states of consciousness that are described as being ineffable and meaningful (Griffiths et al. 2016; Grob et al.…”
BackgroundChing, T. H. W., Grazioplene, R., Bohner, C., Kichuk, S. A., DePalmer, G., D’Amico, E., Eilbott, J., Jankovsky, A., Burke, M., Hokanson, J., et al. (2023) · Frontiers in Psychiatry · doi:10.3389/fpsyt.2023.1178529 · Cited by 29
Siva, J. B., Barba, T., Kettner, H., Kuc, J., Nutt, D., Carhart-Harris, R. L., & Erritzøe, D. (2024) · Journal of Psychopharmacology · doi:10.1177/02698811231224217 · Cited by 34
“The CEQ assessed the unpleasant effects of psychedelic drugs (Barrett et al., 2016).”
BackgroundStrategies for resolving challenging psychedelic experiences: insights from a mixed-methods study
Wood, M. J., McAlpine, R. G., & Kamboj, S. K. (2024) · Scientific Reports · doi:10.1038/s41598-024-79931-w · Cited by 29
Liechti, M. E., & Holze, F. (2021) · Current topics in behavioral neurosciences · doi:10.1007/7854_2021_270 · Cited by 37
Mind the Psychedelic Hype: Characterizing the Risks and Benefits of Psychedelics for Depression
Meling, D., Ehrenkranz, R. C., Nayak, S. M., Aicher, H., Funk, X., van Elk, M., Graziosi, M., Bauer, P. R., Scheidegger, M., & Yaden, D. B. (2024) · Psychoactives · doi:10.3390/psychoactives3020014 · Cited by 35
5-MeO-DMT: An atypical psychedelic with unique pharmacology, phenomenology & risk?
Dourron, H. M., Nichols, C. D., Simonsson, O., Bradley, M. K., Carhart-Harris, R. L., & Hendricks, P. S. (2023) · Psychopharmacology · doi:10.1007/s00213-023-06517-1 · Cited by 36
“…knowledge, reactivations are not regularly reported with the use of typical psychedelics (Müller et al. 2022), even after challenging experiences (Barrett et al. 2016; Carbonaro et al. 2016; Gashi et al. 2021), and flashbacks are rarely reported with MDMA in the treatment of post-traumatic…”
Classic psychedelics, health behavior, and physical health
Simonsson, O., Hendricks, P. S., Chambers, R., Osika, W., & Goldberg, S. B. (2022) · Therapeutic Advances in Psychopharmacology · doi:10.1177/20451253221135363 · Cited by 30
Zeifman, R. J., Kettner, H., Pagni, B. A., Mallard, A. J., Roberts, D. E., Erritzøe, D., Ross, S., & Carhart-Harris, R. L. (2023) · Scientific Reports · doi:10.1038/s41598-023-40856-5 · Cited by 34
Pontual, A. A. D. D., Tófoli, L. F., Corradi-Webster, C. M., van Oorsouw, K. I. M., Delgado, A. R. O., & Ramaekers, J. G. (2022) · Frontiers in Psychology · doi:10.3389/fpsyg.2022.857372 · Cited by 35
“Challenging experience questionnaire The CEQ is a self-report instrument developed and validated in 2016 by Barret and Griffiths (Barrett et al., 2016).”
BackgroundMethodInside bad trips: Exploring extra-pharmacological factors
Oña, G. (2018) · Journal of Psychedelic Studies · doi:10.1556/2054.2018.001 · Cited by 26
“…& Blumen fi eld, 1967; Heaton, 1975; Kleber, 1967; Malleson, 1971; Smart & Bateman, 1967; Strassman, 1984), few studies speci fi cally focus on bad trips (Barrett, Bradstreet, Leoutsakos, Johnson, & Grif fi ths, 2016; Carbonaro et al., 2016; Cohen, 1960; Ungerleider, Fisher, Fuller, & Caldwell, 1968).”
Calder, A. E., & Hasler, G. (2024) · Journal of Affective Disorders · doi:10.1016/j.jad.2024.08.091 · Cited by 28
Stocker, K., Hartmann, M., Ley, L., Becker, A., Holze, F., & Liechti, M. E. (2023) · Journal of Psychopharmacology · doi:10.1177/02698811231199112 · Cited by 29
“Besides work associated with the CEQ (Barrett et al., 2016; cf. above), the only published studies we are aware of that have also analyzed some of the 57 PES items that do not represent Stace-based mystical experience are some studies from our research group (Becker et al., 2022a; Becker et al.,…”
BackgroundMethodInfluentialAday, J. S., McAfee, J., Conroy, D. A., Hosanagar, A., Tarnal, V., Weston, C. L., Scott, K., Horowitz, D., Geller, J. A., Harte, S. E., et al. (2025) · Frontiers in Pain Research · doi:10.3389/fpain.2025.1527783 · Cited by 22
Breeksema, J. J., Niemeijer, A. R., Kuin, B., Veraart, J. K. E., Vermetten, E. H. G. J. M., Kamphuis, J., van den Brink, W., & Schoevers, R. A. (2023) · Psychopharmacology · doi:10.1007/s00213-023-06388-6 · Cited by 32
The safety of psilocybin-assisted psychotherapy: A systematic review
de Freitas, R. R., Gotsis, E. S., Gallo, A. T., Fitzgibbon, B. M., Bailey, N. W., & Fitzgerald, P. B. (2024) · Australian & New Zealand Journal of Psychiatry · doi:10.1177/00048674241289024 · Cited by 29
“Initial efforts have been made in the field to better characterise the challenging experience (Barrett et al., 2016; Dworatzyk et al., 2022) and the emotional breakthrough or cathartic experience (Roseman et al., 2019), as well as their potential to predict therapeutic efficacy in clinical trial…”
Psychological effects of psychedelics in adolescents
Izmi, N., Carhart-Harris, R. L., & Kettner, H. (2024) · Frontiers in Child and Adolescent Psychiatry · doi:10.3389/frcha.2024.1364617 · Cited by 26
Psychedelic therapy in depression and substance use disorders
Korkmaz, N. D., Çıkrıkçılı, U., Akan, M., & Yücesan, E. (2024) · European Journal of Neuroscience · doi:10.1111/ejn.16421 · Cited by 29
“It is more common in vulnerable individuals in unsuitable environmental conditions that are generally not under expert control (Barrett et al., 2016).”
Safety pharmacology of acute psilocybin administration in healthy participants
Straumann, I., Holze, F., Becker, A., Ley, L., Halter, N., & Liechti, M. E. (2024) · Neuroscience Applied · doi:10.1016/j.nsa.2024.104060 · Cited by 30
“Therefore, inducing mostly positive effects is desirable, although challenging experiences may also have therapeutic potential (Barrett et al., 2016; Carbonaro et al., 2016; Gashi et al., 2021).”
The therapeutic potential of psychedelics: the European regulatory perspective
Butlen‐Ducuing, F., McCulloch, D. E.-W., Haberkamp, M., Mattila, T. K., Bałkowiec-Iskra, E., Aislaitner, G., Balabanov, P., Lundberg, J., Stenbæk, D. S., Elferink, A. J. A., et al. (2023) · The Lancet · doi:10.1016/s0140-6736(23)00264-7 · Cited by 29
Rossi, G. N., Hallak, J. E. C., Bouso, J. C., & SANTOS, R. G. D. (2022) · Expert Opinion on Drug Safety · doi:10.1080/14740338.2022.2066650 · Cited by 26
“Related to this, challenging experiences and bad trips may emerge after serotoninergic hallucinogen administration [28,43,44].”
BackgroundPsychedelic experiences and long-term spiritual growth: a systematic review
Schutt, W. A., Exline, J. J., Pait, K. C., & Wilt, J. A. (2024) · Current Psychology · doi:10.1007/s12144-024-06272-2 · Cited by 30
“…addictive, psy-chedelic use carries important risks, including impaired judgment (Nichols, 2016), “bad trips” (intense, frightening experiences; Barrett et al., 2016; Carbonaro et al., 2016, Johnstad, 2021), persisting changes in perception or mood (e.g., Hallucinogen Persisting Perception…”
The Mystical Experience Questionnaire 4-Item and Challenging Experience Questionnaire 7-Item
Strickland, J. C., Garcia‐Romeu, A., & Johnson, M. W. (2024) · Psychedelic Medicine · doi:10.1089/psymed.2023.0046 · Cited by 28
Self-citationEpidemiology of classic psychedelic substances: results from a Norwegian internet convenience sample
Kvam, T.-M., Uthaug, M. V., Andersen, K. A. A., Refsum, B. B., Tunstad, P. A., Stewart, L. H., Jacobsen, H. B., & Grønnerød, C. (2023) · Frontiers in Psychiatry · doi:10.3389/fpsyt.2023.1287196 · Cited by 24
Sepeda, N. D., Clifton, J. M., Doyle, L. Y., Lancelotta, R., Griffiths, R. R., & Davis, A. K. (2019) · Journal of Psychedelic Studies · doi:10.1556/2054.2019.033 · Cited by 26
“Challenging experiences are described as acute physical and psychological experiences that can include feelings of fear, anxiety, paranoia, sadness, loss of sanity, depressed mood, dissociation, and physical distress (Barrett et al., 2016).”
BackgroundMethodSelf-citationDavis, A. K., Levin, A. W., Nagib, P. B., Armstrong, S. B., & Lancelotta, R. L. (2023) · BMJ Open · doi:10.1136/bmjopen-2022-068884 · Cited by 21
“At the end of the experimental drug session, participants will complete paper or computer-based questionnaires (eg, mystical experience, 29 30 psychological insight, 31 challenging experience 32 ) designed to assess acute subjective experiences associated with the psilocybin session.”
BackgroundKaminski, D., & Reinert, J. P. (2023) · Annals of Pharmacotherapy · doi:10.1177/10600280231205645 · Cited by 27
Price, C. J., Sevinc, G., & Farb, N. A. S. (2023) · Brain Sciences · doi:10.3390/brainsci13101396 · Cited by 20
Michael, P., Luke, D. P., & Robinson, O. C. (2023) · Frontiers in Psychology · doi:10.3389/fpsyg.2023.1083356 · Cited by 22
“Significantly, the vast majority of the experiences herein were benign and beneficial, despite the illicit and uncontrolled nature of the usage, which is claimed to elevate the probability of “bad trips” (Barrett et al., 2016), though perhaps less so among such seasoned users, Indeed, having specific recreational inte…”
BackgroundPharmacological and non-pharmacological predictors of the LSD experience in healthy participants
Vizeli, P., Studerus, E., Holze, F., Schmid, Y., Dolder, P. C., Ley, L., Straumann, I., Becker, A., Müller, F., Arikci, D., et al. (2024) · Translational Psychiatry · doi:10.1038/s41398-024-03074-9 · Cited by 25
“Adverse effects of psychedelics are often equated with challenging experiences, commonly referred to as “ bad trips, ” rather than physical complications [17, 47].”
BackgroundHow Important Is a Guide Who Has Taken Psilocybin in Psilocybin-Assisted Therapy for Depression?
Earleywine, M., Low, F., Altman, B. R., & Leo, J. A. D. (2022) · Journal of Psychoactive Drugs · doi:10.1080/02791072.2022.2047842 · Cited by 32
Kruger, D. J., Aday, J. S., Fields, C. W., Kolbman, N., Glynos, N. G., Barron, J., Herberholz, M., & Boehnke, K. F. (2024) · Psychedelic Medicine · doi:10.1089/psymed.2024.0011 · Cited by 24
“15,16 Long-term negative effects may persist well after the acute psy-chedelic experience, 17 including re-experiencing adverse mental or physiological states (e.g., nausea).”
Nikolaidis, A., Lancelotta, R., Gukasyan, N., Griffiths, R. R., Barrett, F. S., & Davis, A. K. (2022) · Journal of Affective Disorders · doi:10.1016/j.jad.2022.12.042 · Cited by 26
Self-citationScoping Review of Experiential Measures from Psychedelic Research and Clinical Trials
Herrmann, Z. M., Earleywine, M., Leo, J. A. D., Slabaugh, S., Kenny, T., & Rush, A. J. (2022) · Journal of Psychoactive Drugs · doi:10.1080/02791072.2022.2125467 · Cited by 21
“Paranoia did not covary significantly with impact ratings (Barrett et al. 2016).”
BackgroundMethodInfluentialHübner, S., Haijen, E. C. H. M., Kaelen, M., Carhart-Harris, R. L., & Kettner, H. (2021) · Journal of Medical Internet Research · doi:10.2196/25973 · Cited by 20
“…[52]; the Mystical Experience Questionnaire [53] that assesses acute positive peak experiences; the Challenging Experience Questionnaire [54] that is a measure of unpleasant affective, cognitive, and somatic difficulties experienced during psychedelic use; the Ego Dissolution Inventory…”
Effects of Psychedelics in Older Adults: A Prospective Cohort Study
Kettner, H., Roseman, L., Gazzaley, A. H., Carhart-Harris, R. L., & Pasquini, L. (2024) · American Journal of Geriatric Psychiatry · doi:10.1016/j.jagp.2024.05.007 · Cited by 19
“2 For example, elevated baseline well-being levels in OA are in accordance with representative population level studies showing that in wealthy English-speaking countries, happiness and hedonic experiences are lowest around ages 45 − 54 and tend to increase with age, following an inverted U-shape.”
ResultPsychedelics and the ‘inner healer’: Myth or mechanism?
Peill, J. M., Marguilho, M., Erritzøe, D., Barba, T., Greenway, K. T., Rosas, F. E., Timmermann, C., & Carhart-Harris, R. L. (2024) · Journal of Psychopharmacology · doi:10.1177/02698811241239206 · Cited by 24
“Developed by Barrett et al. (2016), the challenging experience questionnaire (CEQ) assesses challenging events during psychedelic experiences using a 26-item, 5-point Likert-type scale.”
BackgroundThe psychedelic effects of cannabis: A review of the literature
Wolinsky, D., Barrett, F. S., & Vandrey, R. G. (2023) · Journal of Psychopharmacology · doi:10.1177/02698811231209194 · Cited by 26
“The identification of this response pattern helped lead to the development of the Challenging Experience Questionnaire (CEQ), a psychometric scale with validity in assessing clinical response to psychedelic treatments (Barrett et al., 2016; Herrmann et al., 2022).”
BackgroundSelf-citationLanguage as a Window Into the Altered State of Consciousness Elicited by Psychedelic Drugs
Tagliazucchi, E. (2022) · Frontiers in Pharmacology · doi:10.3389/fphar.2022.812227 · Cited by 25
Dworatzyk, K., Jansen, T., & Schmidt, T. T. (2022) · PLoS ONE · doi:10.1371/journal.pone.0264927 · Cited by 19
GH001 vs Placebo in Patients With Treatment-Resistant Depression
Cubała, W. J., Bajbouj, M., Bauer, M., Baune, B. T., Cardoner, N., Devlin, F., Doolin, K., Herrero, R. D., Elices, M., Feeney, A., et al. (2026) · JAMA Psychiatry · doi:10.1001/jamapsychiatry.2026.0096 · Cited by 18
Walther, R. F. E., & van Schie, H. T. (2024) · Psychoactives · doi:10.3390/psychoactives3030026 · Cited by 20
“It encompasses seven key domains: fear, grief, physical distress, insanity, isolation/alienation, death, and paranoia [194].”
Low, F., & Earleywine, M. (2023) · Journal of Psychoactive Drugs · doi:10.1080/02791072.2023.2228303 · Cited by 17
“A subset of the Challenging Experience Questionnaire (CEQ; Barrett et al. 2016) was used to assess challenging psychological experiences that occurred during the acute effects of the psychedelic trip.”
BackgroundMethodInfluentialPsychedelic Science of Spirituality and Religion: An Attachment-Informed Agenda Proposal
Cherniak, A. D., Brulin, J. G., Mikulincer, M., Östlind, S., Carhart-Harris, R. L., & Granqvist, P. (2022) · International Journal for the Psychology of Religion · doi:10.1080/10508619.2022.2148061 · Cited by 25
“However, if challenging experiences are processed and integrated into a coherent narrative, they may also be an important part of the therapeutic process (Barrett et al., 2016; Gashi et al., 2021).”
Set and setting of psychedelics for therapeutic use in psychiatry: A systematic review
Estric, C., Duron, T., Kabani, S., & López‐Castromán, J. (2025) · Journal of Psychopharmacology · doi:10.1177/02698811251338214 · Cited by 18
“The use of scales such as the Challenging Experience Questionnaires (Barrett et al., 2016), which assesses psychiatric side effects such as psychological distress and depressed mood, could help to anticipate an exacerbation of symptoms in populations affected by psychiatric disorders.”
Concurrent stress modulates the acute and post-acute effects of psilocybin in a sex-dependent manner
Farinha‐Ferreira, M., Miranda‐Lourenço, C., Galipeau, C., Lenkei, Z., & Sebastião, A. M. (2024) · Neuropharmacology · doi:10.1016/j.neuropharm.2024.110280 · Cited by 20
Psychedelic risks and benefits: A cross-sectional survey study
Goldy, S. P., Du, B. A., Rohde, J. S., Nayak, S. M., Strickland, J. C., Ehrenkranz, R. C., Levine, M., Barrett, F. S., & Yaden, D. B. (2024) · Journal of Psychopharmacology · doi:10.1177/02698811241292951 · Cited by 18
“Similarly, Simonsson et al. (2023) found that very large doses were a positive predictor of CEQ scores (as were other contextual factors, such as lack of psychological support).”
InfluentialSelf-citationPsychedelics and disorders of consciousness: the current landscape and the path forward
Cardone, P., Alnagger, N., Annen, J., Bicego, A., Gosseries, O., & Martial, C. (2024) · Neuroscience of Consciousness · doi:10.1093/nc/niae025 · Cited by 18
“Despite this, psychedelic drug administration has the potential to result in unpleasant experiences, sometimes associated with feelings of anxiety, dysphoria, and confusion, commonly referred to as a ‘bad trip’ (Strassman 1984, Barrett et al. 2016).”
BackgroundEngel, L. B., Thal, S. B., & Bright, S. J. (2022) · Contemporary Drug Problems · doi:10.1177/00914509221121420 · Cited by 30
“…colloquially termed “bad trips,” have been extensively documented in online, anecdotal bioassay reports (e.g., Erowid.org, n.d.) and clinical investigations of substance-assisted psychotherapy (Barrett et al., 2016; Carbonaro et al., 2016; Garcia-Romeu & Richards, 2018; Kaelen et al., 2018).”
Erritzøe, D., Barba, T., Benway, T. A., Joel, Z., Good, M., Layzell, M., Baker-Jones, M., Campbell, G., Murphy-Beiner, A., Rands, P., et al. (2026) · Nature Medicine · doi:10.1038/s41591-025-04154-z · Cited by 15
Lewis, B. R., Hendrick, J., Byrne, K., Odette, M. M., Wu, C., & Garland, E. L. (2025) · PLoS Medicine · doi:10.1371/journal.pmed.1004519 · Cited by 19
“We administered experiential measures, including the Mystical Experience Questionnaire (MEQ-30) [38], Challenging Experience Questionnaire (CEQ) [39], and NADA-state [40] at the end of either the psilocybin dosing day or the MBSR meditation retreat to all participants.”
Further education in psychedelic-assisted therapy – experiences from Switzerland
Aicher, H., Müller, F., & Gasser, P. (2025) · BMC Medical Education · doi:10.1186/s12909-025-06871-y · Cited by 18
“Sometimes, patients go through very challenging experiences, characterized by anxiety, doubt, pain, despair, suffering, and hopelessness, or also boredom [6].”
Experiential Training in Psychedelic‐Assisted Therapy: A Risk‐Benefit Analysis
Rosenbaum, D., Hare, C., Hapke, E., Herman, Y., Abbey, S. E., Sisti, D. A., & Buchman, D. Z. (2024) · The Hastings Center Report · doi:10.1002/hast.1602 · Cited by 18
Majić, T., Sauter, M., Bermpohl, F., & Schmidt, T. (2021) · Journal of Psychopharmacology · doi:10.1177/0269881121991554 · Cited by 14
“Exploratory testing for correlations with the effects reported in terms of MEQ and CEQ items revealed a positive correlation (rs = 0.1604, p = 0.0031) between dosage and the ‘feeling that you experienced something profoundly sacred and holy’ only, which is one facet of mystical experiences as typically reported under…”
MethodInfluentialGriffiths, R. R., Jesse, R., Richards, W. A., Johnson, M. W., Sepeda, N. D., Bossis, A. P., & Ross, S. (2025) · Psychedelic Medicine · doi:10.1089/psymed.2023.0044 · Cited by 17
“In this version of the questionnaire, the ratings were based on data from three larger questionnaires (see Barrett et al., 2016 for details): Hal-lucinogen Rating Scale, 54 5-Dimension Altered States of Consciousness, 55 and the States of Consciousness Questionnaire.”
Self-citationLongitudinal associations of naturalistic psychedelic use with psychotic and manic symptoms
Simonsson, O., Goldberg, S. B., Osika, W., Stenfors, C. U. D., Chaturvedi, S., Swords, C. M., Narayanan, J., & Hendricks, P. S. (2025) · Psychological Medicine · doi:10.1017/s0033291725000716 · Cited by 19
“…were asked to recall their most intense psychedelic experience during the study period and complete the Challenging Experiences Questionnaire (CEQ; Barrett, Bradstreet, Leoutsakos, Johnson, & Griffiths, 2016) and the Psychological Insight Questionnaire (PIQ; Davis et al., 2021), which were…”
Jones, G. M., Lowe, M. X., Nayak, S. M., Sepeda, N. D., Kettner, H., Carhart-Harris, R. L., Jackson, H., & Garcia‐Romeu, A. (2024) · Journal of Affective Disorders · doi:10.1016/j.jad.2024.10.058 · Cited by 12
Korthuis, P. T., Hoffman, K. A., Wilson‐Poe, A. R., Luoma, J. B., Bazinet, A. D., Pertl, K., Morgan, D. L., Cook, R., Bielavitz, S., Myers, R., et al. (2024) · Journal of Psychopharmacology · doi:10.1177/02698811241257839 · Cited by 16
“Measures used in psilocybin clinical trials (Herrmann et al., 2023) such as the Challenging Experiences Questionnaire (26 items) (Barrett et al., 2016) and the Mystical Experiences Questionnaire (30 items) (Maclean et al., 2012) are well-vali-dated when used in controlled clinical trial settings…”
Atiq, M. A., Baker, M. R., Voort, J. L. V., Vargas, M. V., & Choi, D. (2024) · Psychopharmacology · doi:10.1007/s00213-024-06599-5 · Cited by 16
“After controlling for participant-rated drug intensity (item 98 on HRS scale), significant effects of total MEQ scores on changes in five of six primary outcome measures (HADS T, HADS A, BDI, STAI S, STAI T) were found at six weeks following the psilocybin dose.”
InfluentialPilecki, B. C., Luoma, J. B., & Lear, K. M. (2024) · Journal of Psychedelic Studies · doi:10.1556/2054.2024.00295 · Cited by 12
“Participants reported a small, nonsigni fi - cant reduction in general psychological in fl exibility as (Barrett et al., 2015, 2016). measured by the AAQ-II at 2-week follow up ( g 5 0.44), and a larger, statistically signi fi cant effect at 6-month follow up ( g 5 0.86).”
BackgroundMethodInfluentialPrimum non nocere: The onus to characterize the potential harms of psychedelic treatment
Ghaznavi, S., Ruskin, J. N., Haggerty, S. J., King, F., & Rosenbaum, J. F. (2025) · American Journal of Psychiatry · doi:10.1176/appi.ajp.20230914 · Cited by 12
Elfrink, S., & Bergin, L. (2025) · Frontiers in Psychology · doi:10.3389/fpsyg.2025.1528253 · Cited by 16
Armstrong, S. B., Levin, A. W., Xin, Y., Horan, J., Luoma, J. B., Nagib, P. B., Pilecki, B. C., & Davis, A. K. (2023) · Journal of Psychedelic Studies · doi:10.1556/2054.2023.00245 · Cited by 13
Pontual, A. A. D. D., Tófoli, L. F., Collares, C. F., Ramaekers, J. G., & Corradi-Webster, C. M. (2021) · Frontiers in Psychology · doi:10.3389/fpsyg.2021.679016 · Cited by 15
Integrating Psychedelic Medicines and Psychiatry: Theory and Methods of a Model Clinic
Sloshower, J. (2018) · Springer eBooks · doi:10.1007/978-3-319-76720-8_7 · Cited by 16
Key competencies for psychedelic treatment in real-world mental health care settings
Wolff, M., Rutrecht, H. M., Gründer, G., Jungaberle, A., & Jungaberle, H. (2025) · General Hospital Psychiatry · doi:10.1016/j.genhosppsych.2025.09.003 · Cited by 15
Schenberg, E. E. (2025) · Pharmacology Research & Perspectives · doi:10.1002/prp2.70097 · Cited by 14
Validation of the imperial psychedelic predictor scale
Angyus, M., Osborn, S., Haijen, E. C. H. M., Erritzøe, D., Peill, J. M., Lyons, T., Kettner, H., & Carhart-Harris, R. L. (2024) · Psychological Medicine · doi:10.1017/s0033291724002204 · Cited by 20
“…2015; Johnson, Garcia-Romeu, Cosimano, & Griffiths, 2014; Roseman et al., 2018; Studerus, Gamma, & Vollenweider, 2010), ‘ challenging experiences ’ (Barrett, Bradstreet, Leoutsakos, Johnson, & Griffiths, 2016; Gashi, Sandberg, & Pedersen, 2021; Roseman et al., 2018), and ‘ emotional breakthrough ’…”
Darke, S., Duflou, J., Peacock, A., Farrell, M., Hall, W., & Lappin, J. M. (2024) · Addiction · doi:10.1111/add.16518 · Cited by 11
Lowe, M. X., Kettner, H., Jolly, D. R. P., Carhart-Harris, R. L., & Jackson, H. (2024) · Frontiers in Psychiatry · doi:10.3389/fpsyt.2024.1279887 · Cited by 14
Canby, N. K., Lindahl, J. R., Britton, W. B., & Córdova, J. V. (2024) · Consciousness and Cognition · doi:10.1016/j.concog.2024.103655 · Cited by 18
Simonsson, O., Osika, W., Stenfors, C. U. D., Goldberg, S. B., Honk, L., & Hendricks, P. S. (2023) · Psychological Medicine · doi:10.1017/s0033291723003082 · Cited by 16
“…feelings of death or dying during a psychedelic experience have been associated with a retrospective, self-reported decrease in wellbeing (Barrett et al., 2016), the association between more days of loving-kindness or compassion meditation practice in the past week at baseline and less…”
BackgroundAcute Subjective Effects of Psychedelics within and Beyond WEIRD Contexts
Graziosi, M., Singh, M., Nayak, S. M., & Yaden, D. B. (2023) · Journal of Psychoactive Drugs · doi:10.1080/02791072.2023.2255274 · Cited by 15
“The CEQ was found to be reliable and valid and factor analysis demonstrated 7 factors: Fear, Grief, Physical Distress, Insanity, Isolation, Death , and Paranoia (Barrett et al. 2016).”
BackgroundMethodInfluential5-methoxy-N,N-dimethyltryptamine: An ego-dissolving endogenous neurochemical catalyst of creativity
Germann, C. (2019) · bioRxiv · doi:10.1101/578435 · Cited by 11
CCNP Innovations in Neuropsychopharmacology Award
Gobbi, G. (2024) · Journal of Psychiatry and Neuroscience · doi:10.1503/jpn.240037 · Cited by 10
“30,31,169 With regard to the mystical effects of psychedelics, the post-session adverse effects were characterized as spiritual bypassing (meaning that the participant became hyper-spiritual and detached from reality), with a radical shift in worldview associated with ego inflation,…”
BackgroundConsidering distinct positive emotions in psychedelic science
Goldy, S. P., Hendricks, P. S., Keltner, D. J., & Yaden, D. B. (2024) · International Review of Psychiatry · doi:10.1080/09540261.2024.2394221 · Cited by 9
“Although the present work will focus on positive emotions, it is important to note that psychedelics’ acute subjective effects also include negative affect and emotions (e.g. anxiety, fear, paranoia; Barrett et al., 2016; Carbonaro et al., 2016).”
InfluentialPerceived attachment history predicts psychedelic experiences: A naturalistic study
Cherniak, A. D., Mikulincer, M., Brulin, J. G., & Granqvist, P. (2024) · Journal of Psychedelic Studies · doi:10.1556/2054.2024.00330 · Cited by 10
“The validity and reliability of the CEQ have been demonstrated (Barrett et al., 2016).”
BackgroundSchmidt, T. T., Reiche, S., Hage, C. L. C., Bermpohl, F., & Majić, T. (2020) · Scientific Reports · doi:10.1038/s41598-020-78527-4 · Cited by 12
Recalled childhood trauma and post-psychedelic trajectories of change in a mixed-methods study
Simon, G., Tadmor, N., Skragge, M., Evans, J., & Robinson, O. C. (2025) · Scientific Reports · doi:10.1038/s41598-025-26198-4 · Cited by 16
Mathai, D. S., Roberts, D. E., Nayak, S. M., Sepeda, N. D., Lehrner, A. L., Johnson, M. W., Lowe, M. X., Jackson, H., & Garcia‐Romeu, A. (2025) · Journal of Psychoactive Drugs · doi:10.1080/02791072.2025.2461997 · Cited by 14
“Feelings like fear, grief, and isolation have been well characterized in these and other psychedelic narratives (Barrett et al. 2016; Johnstad 2021), but limited research has examined the shame associated with psy-chedelic use.”
InfluentialSelf-citationModlin, N. L., McPhee, T., Zazon, N., Sarang, M., Hignett, R., Pick, S., Cleare, A. J., Williamson, V., & Rucker, J. (2024) · Psychedelic Medicine · doi:10.1089/psymed.2024.0027 · Cited by 10
“20,22,23 In response, psychometric measures such as the Challenging Experience Questionnaire 23 and a wide range of aftercare practices, known as “ psychedelic integration, ” have emerged.”
Stroud, J., Rice, C., Orsini, A., Schlosser, M., Lee, J., Mandy, W., & Kamboj, S. K. (2024) · Psychopharmacology · doi:10.1007/s00213-024-06685-8 · Cited by 11
“To improve interpretability MEQ-30 and CEQ scores were both scaled to a 0–100 range (100 = maximal mysticalness or challenge, e.g., Barrett et al. 2016).”
Adverse Events Should Not Be Surprising in Psychedelic Research
Ehrenkranz, R. C., Agrawal, M., Nayak, S. M., & Yaden, D. B. (2024) · Psychedelic Medicine · doi:10.1089/psymed.2024.0006 · Cited by 9
“28 A discussion of challenging experiences should be part of psychedelic psychoeducation, preparation, and the informed consent process.”
Protective Behavioral Strategies for Psychedelic Use: A Mini Review of the Evidence
Piercey, C. J., Gray, B. A., Sung, A., Henry, D., & Karoly, H. C. (2024) · Psychedelic Medicine · doi:10.1089/psymed.2023.0052 · Cited by 7
“…(EBI; a 6-item scale measuring the resolution of challenging emotions during psychedelic experiences) 56 and the Challenging Experiences Questionnaire (CEQ; a 26-item scale quantifying psychological distress during psychedelic experiences) 12 for their fi rst and most recent psychedelic experiences.”
Ching, T. H. W., Amoroso, L., Bohner, C., D’Amico, E. J., Eilbott, J. A., Entezar, T., Fitzpatrick, M., Fram, G., Grazioplene, R. G., Hokanson, J., et al. (2024) · Frontiers in Psychiatry · doi:10.3389/fpsyt.2023.1278823 · Cited by 10
Rajwani, K., Jacobs, E., Bruce, L., Hokanson, J., Almonte, M. T., Feroz, F., Waldman, E. D., Cheung, K., Levy, N. L., Savulescu, J., et al. (2025) · The Lancet Child & Adolescent Health · doi:10.1016/s2352-4642(25)00208-1 · Cited by 8
Naturalistic psychedelic use and changes in depressive symptoms
Simonsson, O., Hendricks, P. S., Swords, C. M., Osika, W., & Goldberg, S. B. (2025) · Journal of Affective Disorders · doi:10.1016/j.jad.2025.119857 · Cited by 9
“Participants who reported past two-month psychedelic use at T2 were asked to recall their most intense psychedelic experience during that period, complete the Challenging Experiences Questionnaire (Barrett et al., 2016), and identify the dose size and context associated with the experience (Simonsson et al., 2023b).”
Roseby, W., Kettner, H., Roseman, L., Spriggs, M. J., Lyons, T., Peill, J., Giribaldi, B., Erritzøe, D., Nutt, D. J., & Carhart-Harris, R. L. (2025) · Frontiers in Psychology · doi:10.3389/fpsyg.2025.1580663 · Cited by 8
Healy, C. J., Frazier, A., Kirsch, S., Sanford, A., Garcia‐Romeu, A., Todman, M., Varon, J. P., & D'Andrea, W. M. (2025) · Progress in Neuro-Psychopharmacology and Biological Psychiatry · doi:10.1016/j.pnpbp.2025.111361 · Cited by 9
“…panic, confusion, or paranoia, and post-acute challenging experiences, which are predicted by acute challenging experiences, include social disconnection, existential difficulties, or persisting derealization or depersonalization (Barrett et al., 2016; Evans et al., 2023; Simonsson et al., 2023).”
Piercey, C. J., Hetelekides, E. M., & Karoly, H. (2024) · Journal of Cannabis Research · doi:10.1186/s42238-024-00235-x · Cited by 8
“A quadratic relationship between cannabis dose and challenging experiences was also found, such that low doses were associated with lower scores on the Chal-lenging Experiences Questionnaire (CEQ) (Barrett et al. 2016), while high doses were associated with higher CEQ scores.”
BackgroundChildhood trauma, challenging experiences, and posttraumatic growth in ayahuasca use
Cassidy, E. K., Healy, C. J., Henje, E., & D'Andrea, W. M. (2024) · Drug Science Policy and Law · doi:10.1177/20503245241238316 · Cited by 9
“The Challenging Experiences Questionnaire (CEQ) is a 26-item self-report scale evaluating the level of challenge a person perceived during or after a psychedelic experience (Barrett et al., 2016).”
Haeny, A. M., Lopez, J., Grigas, P. A. C., Crouch, M. C., Davis, A. K., & Williams, M. T. (2023) · Journal of Substance Use and Addiction Treatment · doi:10.1016/j.josat.2023.209035 · Cited by 11
Altered States of Consciousness During Ceremonial San Pedro Use
Bohn, A., Kiggen, M. H. H., Uthaug, M. V., van Oorsouw, K. I. M., Ramaekers, J. G., & van Schie, H. T. (2022) · International Journal for the Psychology of Religion · doi:10.1080/10508619.2022.2139502 · Cited by 12
“…connotations of ASC induced by psychedelics, a psychedelic experience may also be challenging, due to for example intense bouts of negative affective and somatic states, potentially leading to what is colloquially called a bad trip (Barrett et al., 2016; Bienemann et al., 2020; Guthrie, 2021).”
BackgroundMethodKnock, E., Siefried, K. J., Bedi, G., Albert, S., Day, R. O., Ezard, N., Ross, M., Liknaitzky, P., & Brett, J. (2025) · Addiction · doi:10.1111/add.70187 · Cited by 9
Ching, T. H. W., Grazioplene, R., Pittenger, C., & Kelmendi, B. (2023) · doi:10.31234/osf.io/ba42z · Cited by 6
Stocker, K., Hartmann, M., Schmid, Y., Vogt, S. B., Becker, A., Ley, L., Straumann, I., Arikci, D., Klaiber, A., Erne, L., et al. (2025) · Journal of Psychopharmacology · doi:10.1177/02698811251397328 · Cited by 9
“…Inventory (EBI; Roseman et al., 2019), the Psychological Insight Questionnaire (PIQ; Davis et al., 2021), the Challenging Experience Questionnaire (CEQ; Barrett et al., 2016), the Ego Dissolution Inventory (EDI; Nour et al., 2016), and the Watts Connectedness Scale (WCS; Watts et al., 2022).”
Olofsson, M., Osika, W., Goldberg, S. B., Hendricks, P. S., Petrović, P., White, T. J. H., Stenfors, C. U. D., Chaturvedi, S., & Simonsson, O. (2025) · International Journal of Drug Policy · doi:10.1016/j.drugpo.2025.105105 · Cited by 10
“Indeed, some studies have found positive associations between the degree of difficulty of the acute challenging psychedelic experience and long-term improvements in well-being (Barrett et al., 2016; Carbonaro et al., 2016).”
Bukovsky, D., Amaev, A., Song, J., Kyte, S., Carmona-Torres, E., Ueno, F., Luca, V. D., Strafella, A. P., Husain, M. I., Graff‐Guerrero, A., et al. (2025) · Progress in Neuro-Psychopharmacology and Biological Psychiatry · doi:10.1016/j.pnpbp.2025.111541 · Cited by 9
Brudner, R. M., Kaczmarek, E. S., Blainey, M. G., Schulz-Quach, C., Meshkat, S., Doyle, Z., Lipsitz, O., Offman, H., Sethi, R., Weiglein, G., et al. (2025) · Journal of Psychopharmacology · doi:10.1177/02698811251346697 · Cited by 10
“…experiences (Bogenschutz et al., 2015; Erritzoe et al., 2018; Griffiths et al., 2011, 2016, 2018; Pahnke, 1969; Roseman et al., 2018; Ross et al., 2016, Russ et al., 2019a) and challenging experiences (Barrett et al., 2016; Carbonaro et al., 2016; Haijen et al., 2018; Roseman et al., 2018).”
Lancelotta, R., DellaCrosse, M. A., Quinn, D., Saniyah, S., Saniyah, M., Gukasyan, N., Narayan, S. K., Nikolaidis, A., Sevelius, J. M., & Davis, A. K. (2025) · Journal of Psychoactive Drugs · doi:10.1080/02791072.2025.2520224 · Cited by 7
“The CEQ helps quantify the intensity and impact of negative experiences, which are important for understanding the full range of psychedelic effects (Barrett et al. 2016).”
Metadata
- Authors
- Barrett, F. S., Bradstreet, M. P., Leoutsakos, J.-M. S., Johnson, M. W., & Griffiths, R. R.
- Affiliations
- Johns Hopkins University (US)
- Corresponding author
- Barrett, Frederick S
- Venue
- Journal of Psychopharmacology
- Publisher
- SAGE Publications
- Published
- 2016-11-19
- Volume
- 30
- Issue
- 12
- Pages
- 1279-1295
- ISSN
- 0269-8811 (ISSN-L)
- 1461-7285
- PMC
- PMC5549781
- OpenAlex
- W2549202270
- Cited by
- 366
- References
- 73
- Citations by year
- 2026: 43 · 2025: 77 · 2024: 93 · 2023: 41 · 2022: 39 · 2021: 32 · 2020: 15 · 2019: 10 · 2018: 13 · 2017: 3
- FWCI
- 11.60
- Type
- journal article
- Language
- en
- Open access
- green
- www.ncbi.nlm.nih.gov
- Locations
- Journal of Psychopharmacology (publishedVersion)
- PubMed (publishedVersion)
- PubMed Central (acceptedVersion)
- Funders
- National Institute on Drug Abuse (R01DA003889, T32DA007209)
- Topics
- Social Sciences › Psychology › Clinical Psychology › Psychedelics and Drug Studies
- Social Sciences › Psychology › Social Psychology › Paranormal Experiences and Beliefs
- Social Sciences › Health › Religion, Spirituality, and Psychology
- Keywords
- psilocybin, challenging experiences, bad trips, questionnaire validation, grief, fear, death, paranoia, isolation, physical distress, altered states of consciousness, meaningfulness, spiritual meaning, well-being
- MeSH terms
- Adult, Affect, Agaricales, Anxiety, Depression, Emotions, Female, Hallucinogens, Humans, Male, Psilocybin, Surveys and Questionnaires
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