Systematic review · 2026
Review of psychedelics for adult ADHD finds no proof of benefit
- Original title
- The Use of Psychedelics in the Treatment of Adult ADHD: A Systematic and Mechanistic Review.
- Authors
- Chmiel J, Malinowska A, Kurpas D
- Journal
- International journal of molecular sciences, 2026
- Molecules
- LSD, Ayahuasca, Other
- Conditions
- Other
- Evidence grade
- Low
- Source
- Read the original paper
The question
Do classical psychedelics, including repeated very small doses, reduce ADHD symptoms in adults?
What they did
Researchers followed PRISMA systematic review methods to search major databases for prospective or experimental studies in adults aged 18 and over who had diagnosed ADHD or high ADHD symptom levels and who took a classical psychedelic. They used standard risk-of-bias tools (RoB 2 for the randomized trial, ROBINS-I for the others). Five studies met the criteria: three online naturalistic microdosing cohorts, one randomized double-blind placebo-controlled phase 2A trial of low-dose LSD, and one before-and-after ayahuasca retreat pilot. Results were described narratively because the studies were too few and too different to pool.
What they found
In the three uncontrolled naturalistic microdosing studies, participants reported short-term drops in ADHD symptom ratings alongside better well-being and mood-related functioning. In the only randomized placebo-controlled trial, both the LSD group and the placebo group improved, and LSD showed no statistically significant advantage on either clinician-rated or self-reported ADHD outcomes. Objective cognitive test results were limited and inconsistent. Safety information outside the supervised trial setting was sparse.
The fine print
Only five studies existed to review, and the abstract does not report how many people they included in total. The naturalistic studies relied on self-selected volunteers, self-reported symptoms and non-standardized dosing, leaving them open to expectancy effects and drop-out bias. Follow-up was short and the review could not separate drug effects from setting, self-monitoring or expectation. This summary is based on the abstract only.
What it means
Positive reports from people microdosing on their own are not matched by the one controlled trial, where placebo did just as well, so current evidence does not support psychedelics as a treatment for adult ADHD.
Evidence grade: Low. A systematic review of only five studies, most of them uncontrolled and self-reported, with findings combined narratively rather than statistically.
This summary is based on the study’s published abstract.