The Afterglow Inventory (AGI): Validation of a new instrument for measuring subacute effects of classic serotonergic psychedelics.
Journal of psychopharmacology (Oxford, England) – March 31, 2025
Source: PubMed
Summary
Classic psychedelics often leave users with a pleasant "afterglow"—a period of enhanced well-being after the main effects fade. To explore this, researchers developed a new questionnaire to assess subacute effects. Their study found that the Afterglow Inventory effectively measures positive outcomes, revealing connections between acute experiences and lasting benefits.
Abstract
Classic psychedelics such as psilocybin and lysergic acid diethylamide are anecdotally associated with the phenomenon of "psychedelic afterglow," a set of predominantly pleasant, temporary psychological effects reported after the acute effects have subsided. Since post-acute effects are crucial for the therapeutic use of psychedelics, an instrument to systematically assess subacute "afterglow" effects is needed. To create and validate a questionnaire to quantify the subacute "afterglow" effects of psychedelics. An international online survey was conducted in English and German. Participants who had consumed a psychedelic (N = 1323) or another non-psychedelic substance (control group, N = 157) within the past 4 weeks were included. An initial list of 97 items was progressively reduced to 24 items. A 5-factor structure best fit the data and showed high internal consistency. The factors included (1) vitality, (2) transpersonal aspects, (3) inspiration/creativity, (4) interpersonal relationships, and (5) relationship to nature. The final 24-item version of the Afterglow Inventory (AGI) effectively differentiated between the psychedelic group and the control group. The overall AGI score positively correlated with the intensity (r = 0.165; p < 0.001) and positive valence (r = 0.251; p < 0.001) of the acute psychedelic effects. The AGI is a novel scale for quantifying positive subacute ("afterglow") effects of psychedelics. The use of the AGI could lead to a better understanding of the interplay between acute, subacute, and long-term effects of psychedelics. Insights could also be gained into how different substances, dosages, and extra-pharmacological factors, such as psychotherapy, might influence outcomes.