ADHD symptoms are not lessened or helped by microdoses of LSD, scientists have concluded, after the first randomised controlled trial found that the psychedelic drug was no more effective than a placebo.
Microdosing psychedelic drugs involves taking them a few times a week in small enough doses to not experience hallucinations, reports New Scientist. Although there is little evidence backing it up, there is a pervasive idea that this can boost well-being, creativity and focus.
Additionally, some studies have shown that people who microdose as a way of treating ADHD do report symptoms improving, but these studies were observational and relied on self-reported data.
To test the drugs’ effects on ADHD more rigorously, Matthias Liechti at the University of Basel in Switzerland and his colleagues conducted the first ever randomised controlled trial of LSD microdosing for ADHD, recruiting 53 adults living in The Netherlands or Switzerland who were diagnosed with ADHD and experienced moderate to severe symptoms.
Twenty-seven of the participants took a 20-microgram dose of LSD twice a week – on the higher end of microdoses, but still only about a fifth of a standard dose – while the rest were given a placebo.
ADHD symptoms were assessed at the start of the study and six weeks later using a 54-point scale, where higher scores indicated more severe symptoms. On average, scores decreased by about seven points in participants taking LSD and nearly nine points in those given a placebo. This isn’t a significant difference, suggesting that LSD is no better than a placebo at improving ADHD symptoms, said Liechti.
However, it could be that the dosage wasn’t right for treating ADHD, he added.
The findings were published in JAMA Psychiatry.
LSD may also need to be taken daily to experience a decrease in symptoms, similar to how current ADHD medications works, said Conor Murray at the University of California-Los Angeles.
“We still need to see whether an acute dose, meaning while the drug is in your body, provides any reduction in symptoms,” he said.
“That is kind of the first step. And if it doesn’t, then you almost don’t even have to ask whether there is any enduring change.”
Study details
Safety and efficacy of repeated low-dose LSD for ADHD treatment in adults: a randomised clinical trial
Lorenz Mueller, Joyce Santos de Jesus, Yasmin Schmid et al.
Published in JAMA Psychiatry on 19 March 2025
Abstract
Importance
Microdosing psychedelics, including lysergic acid diethylamide (LSD), has gained attention for its potential benefits in several psychiatric disorders, including attention-deficit/hyperactivity disorder (ADHD). However, LSD’s efficacy in reducing ADHD symptoms remains unknown.
Objective
To determine the safety and efficacy of repeated low doses of LSD in reducing ADHD symptoms compared with placebo.
Design, Setting, and Participants
This was a 6-week, multicentre, double-blind, placebo-controlled, parallel-group phase 2A randomised clinical trial conducted between December 17, 2021, and December 4, 2023. Data were analysed from March 22, 2024, to August 19, 2024. Outpatient treatment was provided at 2 centres: University Hospital in Basel, Switzerland, and Maastricht University in The Netherlands. Adults aged 18 to 65 years with a prior ADHD diagnosis who presented with moderate to severe symptoms (Adult Investigator Symptom Rating Scale [AISRS] score ≥26 and Clinical Global Impression Severity score ≥4) were eligible for inclusion. Key exclusion criteria included selected current major psychiatric or somatic disorders and the use of potentially interacting medications.
Intervention
Participants received either LSD (20 μg) or placebo twice weekly for 6 weeks (total of 12 doses).
Main Outcome and Measures
The primary outcome was the change in ADHD symptoms from baseline to week 6, assessed by the AISRS and analyzed with a mixed-effects model for repeated measures.
Results
A total of 53 participants were randomised to LSD (n = 27) or placebo (n = 26). Mean (SD) participant age was 37 (12) years, and 22 participants (42%) were female. The LSD group presented a mean AISRS improvement of −7.1 points (95% CI, −10.1 to −4.0). The placebo group presented a mean AISRS improvement of −8.9 points (95% CI, −12.0 to −5.8), with no difference between groups. LSD was physically safe and psychologically well tolerated overall.
Conclusions and Relevance
In this randomised clinical trial, repeated low-dose LSD administration was safe in an outpatient setting, but it was not more efficacious than placebo in reducing ADHD symptoms.
NewScientist article – Microdosing LSD is not an effective ADHD treatment (Open access)
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