Translated from our German original by AI. The German text was researched, written, and edited by the Psychedelia Foundation team and remains the authoritative version.
A randomized, placebo-controlled crossover study in 45 healthy adults provides evidence that a single 100 microgram dose of lysergic acid diethylamide (LSD) can be associated with changes in individual learning and neurophysiology measures days after it is taken. Animal studies had already pointed to longer-term effects of LSD on neuronal plasticity, but comparable data from studies in humans have been limited.
The researchers examined the participants for up to a week after dosing using electroencephalography (EEG), transcranial magnetic stimulation (TMS), blood measurements of the neurotrophic factor Brain-Derived Neurotrophic Factor (BDNF), and tests of motor learning. They also recorded perceived stress and aspects of cognitive flexibility using questionnaires.
Better Consolidation of Movement Sequences and Less Stress
One day after the LSD dose there was a significant improvement in what is known as offline learning of movement sequences. This refers to gains in performance that occur between two practice sessions, in phases without further active training (for example during rest or sleep), when the brain consolidates what has been learned more or less on its own. A week after dosing, participants also reported feeling less stressed and showed improvements in individual aspects of cognitive flexibility.
Lasting Neurophysiological Changes
Significant changes were also found at the neuronal level. In the EEG, LSD acutely reduced the amplitudes of the auditory event-related potentials N1 and P2; changes in the P2 potential were still detectable a week later. With transcranial magnetic stimulation, motor evoked potentials showed larger amplitudes and shorter latencies after the LSD dose. Concentrations of BDNF, the factor important for nerve growth, did not change in peripheral blood.
Methodological Challenges and Context
In the authors’ assessment, the results argue for further work on the influence of LSD on human learning. At the same time, the paper points to important methodological challenges in measuring long-term potentiation (LTP), or long-term synaptic plasticity, in humans. Because only healthy adults were studied, the findings do not allow any direct conclusions about a therapeutic benefit of LSD.
