Dose-response relationships of LSD-induced subjective experiences in humans.
Tim Hirschfeld, Johanna Prugger, Tomislav Majić, Timo T Schmidt
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology October 1, 2023 DOI: 10.1038/s41386-023-01588-2 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Systematic review and meta-analysis Peer reviewed |
|---|---|
| Intervention | LSD |
| Dose | up to 200 μg base |
| Topics | LSD |
| Keywords | Psychedelics Consciousness research Pharmacology |
| Citations | 24 |
| Key findings | Most scales of altered states of consciousness show a sigmoid-like increase with LSD dose, plateauing at around 100 μg, with the strongest modulation in perception and illusory imagination. |
Abstract
Lysergic acid diethylamide (LSD) is a potent classic serotonergic psychedelic, which facilitates a variety of altered states of consciousness. Here we present the first meta-analysis establishing dose-response relationship estimates of the altered states of consciousness induced by LSD. Data extracted from articles identified by a systematic literature review following PRISMA guidelines were obtained from the Altered States Database. The psychometric data comprised ratings of subjective effects from standardized and validated questionnaires: the Altered States of Consciousness Rating Scale (5D-ASC, 11-ASC) and the Mystical Experience Questionnaire (MEQ30). We performed meta-regression analyses using restricted cubic splines for data from studies with LSD doses of up to 200 μg base. Most scales revealed a sigmoid-like increase of effects, with a plateauing at around 100 μg. The most strongly modulated factors referred to changes in perception and illusory imagination, followed by positively experienced ego-dissolution, while only small effects were found for Anxiety and Dread of Ego Dissolution. The considerable variability observed in most factors and scales points to the role of non-pharmacological factors in shaping subjective experiences. The established dose-response relationships may be used as general references for future experimental and clinical research on LSD to compare observed with expected subjective effects and to elucidate phenomenological differences between psychedelics.