RCT · 2026
LSD in healthy volunteers: effects on motor learning, stress and brain signals up to a week
- Original title
- Acute and post-acute neurobehavioral responses to lysergic acid diethylamide in healthy subjects: a randomized controlled study.
- Authors
- Calder AE, Diehl VJ, Lietz MP, et al.
- Journal
- Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 2026
- Molecules
- LSD
- Conditions
- Healthy volunteers
- Participants
- 45
- Evidence grade
- Moderate
- Source
- Read the original paper
The question
Does a single dose of LSD change brain signalling, learning ability, stress and mental flexibility in healthy people, both during the experience and in the days after?
What they did
Forty-five healthy adults (24 women) each received 100 micrograms of LSD and a placebo on separate occasions, in random order, without knowing which was which. For up to a week after each dose, researchers measured brain responses using EEG (electrical recordings from the scalp) and transcranial magnetic stimulation (TMS, magnetic pulses applied to the head that produce muscle responses), plus blood levels of BDNF, a protein linked to brain plasticity. A day after dosing, participants did a sequence-typing task to test motor learning, and a week later they filled in questionnaires on perceived stress and cognitive flexibility.
What they found
Offline motor learning, meaning improvement that appears after practice has stopped, was significantly better the day after LSD than after placebo. One week after LSD, participants reported less perceived stress and higher scores on some aspects of cognitive flexibility. EEG showed that LSD acutely reduced the size of two auditory brain responses (N1 and P2), and the P2 response was still altered one week later. Muscle responses to magnetic brain stimulation were larger and faster under LSD. Blood BDNF levels did not change.
The fine print
This was a healthy-volunteer study, not a treatment trial, so it says nothing about whether LSD helps any medical condition. With 45 people and many different measures, some findings could reflect chance, and the abstract does not give effect sizes or exact statistics. Blinding is difficult with a noticeable drug like LSD, follow-up was only one week, and this summary is based on the abstract alone.
What it means
In a controlled setting, a single dose of LSD was linked to better consolidation of a newly learned motor task the next day, and to lower self-reported stress and somewhat greater mental flexibility a week later, alongside measurable changes in brain signalling. These are early, exploratory findings in healthy people that need replication.
Evidence grade: Moderate. A randomized placebo-controlled crossover trial, but with a modest sample of healthy volunteers, a one-week follow-up and many outcome measures tested at once.
This summary is based on the study’s published abstract.