Evaluation of the peak experience scale as a rapid assessment tool for the strength of a psychoactive experience with 5-MeO-DMT.

Johannes T. Reckweg; Natasha L. Mason; Eef L. Theunissen; Claus B Svendsen; Theis H Terwey; Johannes G. Ramaekers

doi:10.3389/fpsyg.2025.1543640

Evaluation of the peak experience scale as a rapid assessment tool for the strength of a psychoactive experience with 5-MeO-DMT.

Johannes T. Reckweg, Natasha L. Mason, Eef L. Theunissen, Claus B Svendsen, Theis H Terwey, Johannes G. Ramaekers

Frontiers in Psychology 2025 DOI: 10.3389/fpsyg.2025.1543640 (opens in new tab)

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Study at a glance

AI-extracted from the abstract

Characteristics	Observational cohort Peer reviewed
Sample size	84
Population	Healthy volunteers and patients with treatment resistant depression
Intervention	5-MeO-DMT formulation (GH001)
Dose	0 (placebo), 2, 6, 12, 18 mg or incremental individualized dosing regimen (IDR)
Topics	5-MeO-DMT Mystical experience DMT
Keywords	Psychedelic Questionnaire Intensity Assess the strength Highly effective Strong correlation Ratings increased Rapidly assess Valuable Quick way Guide dosing Tool Simple Three-item 5-MEO-DMT: Mebufotenin Unique psychoactive compound Validated Understanding individual responses
Citations	2
Key findings	The three-item Peak Experience Scale is a valid and reliable tool for rapidly assessing the intensity of the 5-MeO-DMT psychedelic experience, showing strong correlation with established measures and dose-dependent increases in ratings.

Abstract

A three-item Peak Experience Scale (PES) was developed to rapidly evaluate the strength of the psychoactive experience, and to guide the dosing regimen, of the psychedelic 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT; mebufotenin). This paper aims to compare the PES with a range of established questionnaires designed to evaluate the psychedelic experience. Data were gathered from three separate studies in which a 5-MeO-DMT formulation (GH001) was administered via pulmonary inhalation to healthy volunteers and patients with treatment resistant depression (N = 84) as either single doses (0 [placebo], 2, 6, 12, 18 mg) or an incremental individualized dosing regimen (IDR). Apart from the PES, participants also completed the Mystical Experience Questionnaire (MEQ-30), the Challenging Experience Questionnaire (CEQ), the Ego Dissolution Inventory (EDI) and the 5-Dimensional Altered States of Consciousness Rating Scale (5D-ASC). The 5-MeO-DMT formulation produced a significant, dose-related increase in PES ratings, with maximal ratings being achieved after the IDR. A principal component analysis (PCA) of the PES items identified a single primary component explaining 83.5% of the variance. PES items also displayed a strong internal consistency (Cronbach's α = 0.896). A PCA across all questionnaires indicated a strong and unidimensional loading of the PES, MEQ, EDI and the 5D-ASC, suggesting high interrelatedness. Likewise, individual ratings on the PES were highly correlated to those on the PES, MEQ, EDI and the 5D-ASC, but not the CEQ. The PES is concluded to be an effective tool to rapidly assess the strength of the psychedelic experience with 5-MeO-DMT. The PES could prove useful to gain fast insight into the strength of a psychedelic dose in individual patients and potentially guide dose and re-dose selection of rapid-acting psychedelics.

Comparable studies

Other observational and cohort studies on 5-MeO-DMT, most cited first.

Study	Year	Design	Participants
A single inhalation of vapor from dried toad secretion containing 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) in a naturalistic setting is related to sustained enhancement of satisfaction with life, mindfulness-related capacities, and a decrement of psychopathological symptoms. Volunteers who inhaled vapor from dried toad secretion at several European locations	2019	Observational cohort	n = 42
Intensity of Mystical Experiences Occasioned by 5-MeO-DMT and Comparison With a Prior Psilocybin Study Individuals at a psychospiritual retreat in Mexico	2018	Observational cohort	n = 20
Neural and subjective effects of inhaled N,N-dimethyltryptamine in natural settings. Healthy and experienced participants	2021	Observational field study	n = 35
A Phase 1, Dose-Ranging Study to Assess Safety and Psychoactive Effects of a Vaporized 5-Methoxy-N, N-Dimethyltryptamine Formulation (GH001) in Healthy Volunteers. Healthy volunteers	2021	Prospective dose-finding study	n = 22
Open-label study of consecutive ibogaine and 5-MeO-DMT assisted-therapy for trauma-exposed male Special Operations Forces Veterans: prospective data from a clinical program in Mexico. Trauma-exposed Special Operations Forces Veterans	2023	Prospective clinical program evaluation	n = 86

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