Single LSD microdoses produced dose-related drug effects but left mood and thinking largely unchanged in healthy volunteers
A 2019 laboratory study gave healthy volunteers single very low doses of LSD — the range people use when 'microdosing' — to test how the doses affected their mood, emotions, and thinking under controlled conditions.
Many people who microdose say very low doses of LSD lift their mood and sharpen their thinking, but this had not been tested in a controlled lab. Twenty healthy young adults each came in four times, a week apart, and on different visits received a dummy pill (placebo) or 6.5, 13, or 26 micrograms of LSD in a random order. Neither the participants nor the researchers scoring them knew which dose was given on a given day. The felt drug effect grew steadily as the dose increased. At the highest dose people also reported more vigor and rated positive images as slightly less positive, but other mood ratings, thinking tasks, and body measures stayed the same. The authors concluded that these microdoses produced orderly, dose-related subjective effects and that a 13-microgram dose might be tested safely in a future repeated-dosing study.
In this randomized, double-blind, placebo-controlled, within-subject dose-response study, 20 healthy young adults each attended four laboratory sessions and received 0 (placebo), 6.5, 13, or 26 μg of LSD in randomized order at 1-week intervals, completing mood questionnaires and behavioral tasks of emotion processing and cognition during the expected peak drug effect, along with cardiovascular and body-temperature measures. LSD produced dose-related subjective effects across the three active doses (6.5, 13, and 26 μg). At the highest dose it also increased ratings of vigor and slightly decreased positivity ratings of images with positive emotional content, while other mood measures, cognition, and physiological measures were unaffected. The authors conclude that single microdoses produced orderly, dose-related subjective effects and that a threshold dose of 13 μg might be used safely in an investigation of repeated administrations.
The authors note that their participants were healthy and without mood disturbances, and that it remains to be determined whether the drug improves mood or cognition in individuals with symptoms of depression; they call for LSD to be examined in populations reporting clinical mood symptoms such as anxiety or depression. They also observe that people who microdose in daily life take the drug every few days, so any beneficial effects may emerge only after repeated administration — whereas this study tested single doses. Design-inherent points: the sample was small and drawn from healthy young adults, not a clinical or veteran population, limiting generalizability to people seeking symptom relief; and because the higher dose was noticeable, participants may have been able to tell active LSD from placebo despite the double-blind design. The authors reported no biomedical financial interests or potential conflicts of interest; the work was supported by National Institutes of Health / NIDA training and research grants.
Single microdoses of LSD produced orderly dose-related subjective effects in healthy volunteers, and these findings indicate that a threshold dose of 13 μg of LSD might be used safely in an investigation of repeated administrations (Bershad et al., 2019, Biological Psychiatry).
Read the full paper →