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Repeated low doses of LSD in healthy adults: A placebo-controlled, dose-response study.

Harriet de Wit, Hanna Molla, Anya K. Bershad, Michael P. Bremmer, Royce Lee

Addiction Biology February 1, 2022 DOI: 10.1111/adb.13143 (opens in new tab)

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Study at a glance

AI-extracted from the abstract
Characteristics Randomized controlled trial Placebo-controlled Double-blind Peer reviewed
Sample size 56
Population Healthy adults
Intervention LSD tartrate
Dose 13 or 26 μg
Duration Four 5-hour drug-administration sessions separated by 3-4 days, followed by a drug-free follow-up session 3-4 days after the last session
Topics LSD
Keywords LSD Microdosing Mood and cognition Clinical research
Citations 82
Key findings Repeated low doses of LSD (13 or 26 μg) produced modest subjective effects but did not improve mood or cognitive performance in healthy adults.

Abstract

The resurgence of interest in using psychedelic drugs, including lysergic acid diethylamide (LSD), in psychiatry has drawn attention to the medically unsupervised practice of 'microdosing'. Thousands of users claim that very low doses of LSD, taken at 3-4-day intervals, improve mood and cognitive function., However, few controlled studies have described the effects of the drug when taken in this way. Here, in a double-blind controlled study, we studied the effects of four repeated doses of LSD tartrate (13 or 26 μg) or placebo, administered to healthy adults at 3-4 day intervals, on mood, cognitive performance and responses to emotional tasks. Participants were randomly assigned to one of three drug conditions: placebo (N = 18), 13 μg LSD (N = 19), or 26 μg LSD (N = 19). They attended four 5-hour drug-administration sessions separated by 3-4 days, followed by a drug-free follow-up session 3-4 days after the last session. LSD (26 μg) produced modest subjective effects including increased ratings of 'feeling a drug effect' and both stimulant-like and LSD-like effects, but the drug did not improve mood or affect performance on psychomotor or most emotional tasks. No residual effects were detected on mood or task performance on the drug-free follow-up session. We conclude that within the context of a controlled setting and a limited number of administrations, repeated low doses of LSD are safe, but produce negligible changes in mood or cognition in healthy volunteers.

Comparable studies

Other randomized controlled trials on LSD, most cited first.

Study Year Design Participants
Safety and Efficacy of Lysergic Acid Diethylamide-Assisted Psychotherapy for Anxiety Associated With Life-threatening Diseases Patients with anxiety associated with life-threatening diseases 2014 Randomized controlled trial n = 12
Dose-Response Study of N,N-Dimethyltryptamine in Humans Experienced hallucinogen users 1994 Double-blind, saline placebo-controlled, randomized study n = 12
Acute Effects of Lysergic Acid Diethylamide in Healthy Subjects Healthy subjects (8 women, 8 men) 2014 Double-blind, randomized, placebo-controlled, crossover study n = 16
Changes in global and thalamic brain connectivity in LSD-induced altered states of consciousness are attributable to the 5-HT2A receptor Healthy human participants 2018 Double-blind, randomized, counterbalanced, cross-over study n = 24
LSD-induced entropic brain activity predicts subsequent personality change. Healthy adults 2016 Balanced-order, placebo-controlled study n = 19

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LSD Microdosing