This data analysis of three studies (n=84) validates a three-item Peak Experience Scale (PES) for rapidly assessing 5-MeO-DMT experiences, demonstrating that the scale shows strong internal consistency (Cronbach’s α=0.896), correlates highly with established psychedelic experience measures (MEQ-30, EDI, 5D-ASC), and could effectively guide dosing regimens for rapid-acting psychedelics.

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

“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.“

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

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

Reckweg and colleagues conducted a comprehensive evaluation of a new assessment tool, the Peak Experience Scale (PES), designed to rapidly measure the strength of a psychoactive experience induced by 5-MeO-DMT (also known as mebufotenin). The authors aimed to validate the PES in comparison to several established psychedelic experience questionnaires and to determine whether it could be effectively used to guide dosing decisions in clinical and experimental settings.

5-MeO-DMT is a potent, fast-acting psychedelic known for its short duration and potential to elicit intense, often ineffable experiences. Prior research has shown that the intensity of the psychedelic experience, including aspects such as ego dissolution and mystical-type effects, is associated with improved mental health outcomes in both healthy individuals and clinical populations. However, tools commonly used to measure these experiences are time-consuming and complex. The PES was developed as a quick, three-item visual analogue scale to assess intensity, loss of control, and the profundity of the experience. An average score of 75 or higher is considered to reflect a “peak experience” (PE).

The study pooled data from three clinical trials in which 5-MeO-DMT was administered to both healthy volunteers and patients with treatment-resistant depression (TRD). These studies aimed to determine if the PES could reliably assess the intensity of psychedelic effects and assist in determining whether additional doses were needed to achieve a PE.

Methods

Overview of the Three Studies

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Find this paper

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

https://doi.org/10.3389/fpsyg.2025.1543640

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Cite this paper (APA)

Reckweg, J. T., Mason, N. L., Theunissen, E. L., Svendsen, C. B., Terwey, T. H., & Ramaekers, J. G. (2025). Evaluation of the peak experience scale as a rapid assessment tool for the strength of a psychoactive experience with 5-MeO-DMT. Frontiers in Psychology, 16, 1543640.

Study details

Compounds studied
5-MeO-DMT Placebo

Topics studied
Healthy Subjects Treatment-Resistant Depression Depression

Study characteristics
Placebo-Controlled Double-Blind Randomized

Participants
84 Humans

Compound Details

The psychedelics given at which dose and how many times

5-MeO-DMT 6 - 18
mg | 3x

Linked Research Papers

Notable research papers that build on or are influenced by this paper

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
This Phase I study assessed the safety and psychoactive effects of 5-MeO-DMT (GH001) in healthy volunteers (n=22). Single doses of 6, 12, and 18 mg of the inhaled GH001 formulation of 5-MeO-DMT were able to induce a peak experience in a minority of participants. An individualized dose escalation regimen produced a peak experience in every participant. Measures of cognition, mood, and well-being were not affected by 5-MeO-DMT. Adverse events were generally mild and resolved spontaneously.

A phase 1/2 trial to assess safety and efficacy of a vaporized 5-methoxy-N,N-dimethyltryptamine formulation (GH001) in patients with treatment-resistant depression
This two-part clinical trial (n=16) investigated the safety and potential antidepressant effects of vaporized 5-MeO-DMT (GH001) in patients with treatment-resistant depression (TRD). Phase I (n=8) tested two single doses (12mg and 18mg) for safety, while Phase II (n=8) evaluated an individualized dosing regimen with up to three increasing doses (6mg, 12mg, 18mg) in a single day for efficacy. The results showed GH001 was well-tolerated and had potent and rapid antidepressant effects, with 87.5% of patients in the Phase 2 group achieving remission by day seven.

Linked Clinical Trial

Safety of GH001 in Healthy Volunteers
The aim of the study is to investigate the safety of GH001 (containing 5-methoxy-dimethyltryptamine; 5-MeO-DMT), and its dose-related psychoactive effects in healthy volunteers.

Clinical Study of GH001 in Depression
The aim of the study is to investigate the safety of GH001 (containing 5-methoxy-dimethyltryptamine; 5-MeO-DMT), and to investigate its effects on severity of depressive symptoms, and its dose-related psychoactive effects in patients with Treatment-Resistant Depression (TRD).

Pharmacokinetics of GH001 in Healthy Volunteers
The primary objective of this study is to investigate the serum pharmacokinetics of 5-MeO-DMT and its metabolite, bufotenine in healthy volunteers.