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TOPLINE:

Twice-weekly administration of low-dose lysergic acid diethylamide (LSD) over 6 weeks was safe in adults with attention-deficit/hyperactivity disorder (ADHD) but was no better than placebo in alleviating symptoms, a new study showed.

METHODOLOGY:

• A 6-week, double-blind, phase 2A randomized clinical trial was conducted at one center each in Switzerland and the Netherlands between 2021 and 2023.
• Overall, 53 adults (mean age, 37 years; 58% women) previously diagnosed with ADHD and with moderate to severe symptoms of the condition were randomly assigned to receive either low-dose LSD (n = 27) or placebo (n = 26) twice weekly in an outpatient setting.
• The primary outcome was the least squares mean change in ADHD symptoms, assessed from baseline to week 6 using the Adult ADHD Investigator Symptom Rating Scale (AISRS).
• Covariates were baseline AISRS score, sex, and age.

TAKEAWAY:

• Improvements in mean AISRS scores in the LSD and placebo groups were −7.1 and −8.9, respectively, with no significant difference between the groups.
• The LSD and placebo groups reported 124 and 64 adverse events (AEs), respectively, with headache, nausea, fatigue, insomnia, and visual alterations being the most common treatment-related AEs.
• No serious AEs, deaths, or new suicidal ideations were observed during the study.

IN PRACTICE:

“These findings indicate that observed benefits of psychedelic microdosing may be attributable more to expectancy than to pharmacological effects of the psychedelic itself,” the investigators wrote.

SOURCE:

The study was led by Lorenz Mueller, MD, University Hospital Basel, Basel, Switzerland. It was published online on March 19 in JAMA Psychiatry.

LIMITATIONS:

The trial was powered to find a large effect size, and very small effects may have been missed. Most participants were enrolled at one site because of logistic problems. Additionally, the study only tested twice-weekly dosing with a relatively high fixed dose of LSD, which may not have accounted for potential interindividual variability in response to psychedelics.

DISCLOSURES:

The study was funded by Mind Medicine. Three of the investigators reported receiving funds, grants, or consulting fees from Mind Medicine or Clerkenwell Health, during the conduct of the study or outside the submitted work.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.