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 quickly gauge the intensity of the psychoactive experience with the psychedelic 5-MeO-DMT and to guide dosing. Data came from three studies involving 84 healthy volunteers and patients with treatment-resistant depression who inhaled a 5-MeO-DMT formulation at doses of 0 (placebo), 2, 6, 12, or 18 mg, or an incremental individualized dosing regimen. PES ratings increased significantly with dose, peaking after the individualized regimen. The scale showed strong internal consistency and high correlation with other psychedelic assessment tools like the Mystical Experience Questionnaire and Ego Dissolution Inventory, but not with the Challenging Experience Questionnaire. The PES is an effective, simple tool for rapidly assessing psychedelic experience strength and may help guide dosing of rapid-acting psychedelics.

Study at a glance

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.