Neurosci Appl
October 26, 2022
Eline Haijen, Petra P M Hurks, Kim P. C. Kuypers
17 citations
Adults with ADHD who microdosed classic psychedelics on their own initiative reported reduced ADHD symptoms and improved well-being after two and four weeks, compared with their baseline. Performance on a time perception task did not improve. Taking conventional ADHD medication alongside microdosing or having other mental health conditions did not alter the effects on symptoms or well-being after four weeks. The authors call for placebo-controlled experiments to determine whether microdosing offers a genuine benefit beyond the placebo effect.
JAMA Psychiatry
June 1, 2025
Lorenz Mueller, Joyce Santos de Jesus, Yasmin Schmid et al.
14 citations
Repeated low doses of LSD (20 μg twice weekly for six weeks) did not reduce ADHD symptoms more than placebo in adults with moderate-to-severe ADHD. In a double-blind randomized trial with 53 participants, the LSD group showed an average 7.1-point improvement on the ADHD symptom scale, while the placebo group improved by 8.9 points—a difference that was not statistically significant. The treatment was physically safe and psychologically well tolerated. The findings suggest that microdosing LSD, despite popular interest, offers no advantage over placebo for ADHD symptom relief.
European Psychiatry
January 1, 2024
Eline Haijen, Petra P M Hurks, Kim P. C. Kuypers
10 citations
Adults with severe ADHD symptoms who microdosed psychedelics reported better emotion regulation and some empathy improvements in an initial uncontrolled study. A second study with a control group found that after four weeks, ADHD symptoms were lower in the microdosing group than in those taking conventional ADHD medication. However, only one emotion regulation measure—expressive suppression—remained improved after accounting for the control group. The findings suggest microdosing may help with ADHD symptoms and certain emotion regulation strategies, but there was no evidence for effects on empathy.
Frontiers in Psychiatry
October 16, 2023
Eline Haijen, Petra P M Hurks, Kim P. C. Kuypers
6 citations
Adults with ADHD who microdosed psychedelics for four weeks showed increased trait mindfulness—specifically the ability to describe and not judge inner experiences—and decreased neuroticism, while other personality traits like conscientiousness, extraversion, agreeableness, and openness remained unchanged. These changes occurred regardless of whether participants also used conventional ADHD medication or had other mental health diagnoses. The findings suggest that microdosing may alter otherwise stable psychological traits in this population, though placebo-controlled studies are needed to confirm the effects.
Current Opinion in Psychology
August 6, 2025
Iva Totomanova, Eline Haijen, Petra P M Hurks et al.
5 citations
Regular use of low doses of LSD or psilocybin, known as microdosing, has been studied in 57 human studies. Reported benefits include improved mood, enhanced cognition, social functioning, and mental health, but findings are inconsistent and largely based on self-reports. Adverse effects such as anxiety, physical discomfort, and cognitive disruption are also common. Outcomes vary greatly by individual and are shaped by expectations, context, and baseline state. Experimental studies of single doses often yield null findings, while observational studies of repeated use report more benefits. The evidence remains inconclusive and warrants caution.
International review of neurobiology
January 1, 2025
Iva Totomanova, Eline Haijen, Petra P M Hurks et al.
Small doses of LSD and psilocybin produce subtle acute effects on neural connectivity, brain electrophysiology, blood pressure, sleep duration, pain perception, temporal processing, and mood, and reduce symptoms of depression and obsessive-compulsive behavior in patient samples. Extra-pharmacological factors such as baseline subjective state, expectations, and individual differences in drug metabolism influence treatment outcomes. Controlled microdosing studies suggest potential therapeutic applications, but large-scale clinical trials are still needed.