Psilocybin microdosing does not affect emotion-related symptoms and processing: A preregistered field and lab-based study

This double-blind placebo-controlled microdosing study (n=75) showed that psilocybin microdoses (0.7g dried truffles, 15mg psilocybin, about 1/10th a high dose) didn’t alter self-awareness or modulated emotion processing. The confirmatory analysis also didn’t find any effects, but an exploratory analysis did show some reduction of depression and stress in only the first block.


Background: Microdoses of psychedelics (i.e. a sub-hallucinogenic dose taken every third day) can reduce symptoms of depression, anxiety and stress according to anecdotal reports and observational studies. Research with medium to high doses of psilocybin points towards potential underlying mechanisms, including the modulation of emotion and interoceptive processing.

Aims: In this preregistered study, we investigated whether psilocybin microdoses alter self-reported interoceptive awareness and whether repeated microdosing over 3 weeks modulates emotion processing and reduces symptoms of anxiety and depression.

Methods: We used a double-blind, placebo-controlled, within-subject crossover design. Participants completed the Multidimensional Assessment of Interoceptive Awareness Questionnaire 1½ h after self-administering their second dose (or placebo), and the emotional go/no-go task and the shortened Depression Anxiety Stress Scale 1½ h after self-administering their seventh dose.

Results: Our confirmatory analyses revealed that psilocybin microdosing did not affect emotion processing or symptoms of anxiety and depression compared with placebo. Our exploratory analyses revealed that psilocybin microdosing did not affect self-reported interoceptive awareness, that symptoms of depression and stress were significantly reduced in the first block compared with baseline, that participants broke blind in the second block and that there was no effect of expectations. Further research in a substance-naïve population with clinical range anxiety and depressive symptoms is needed to substantiate the potential beneficial effects of microdosing.”

Authors: Josephine Marschall, George Fejer, Pascal Lempe, Luisa Prochazkova, Martin Kuchar, Katerina Hajikova & Michiel van Elk

Study details

Compounds studied

Topics studied

Study characteristics
Placebo-Controlled Double-Blind

75 Humans


Authors associated with this publication with profiles on Blossom

Michiel van Elk
Michiel van Elk is an Assistant Professor at the unit Cognitive Psychology of the Institute of Psychology, at Leiden University.

George Fejer
George Fejer is a Research Assistant at the Religion Cognition & Behavior Lab, investigating the placebo effects of psychedelics related to prior expectations, personality traits, and the set and setting. He is also working as a team coordinator of ALIUS, an interdisciplinary collaborative network of researchers, involving neuroscientists, psychologists, philosophers of mind, psychiatrists, and anthropologists, who are dedicated to the development of a systematic and scientific model of consciousness supported by both theoretical work and experimental studies.

Compound Details

The psychedelics given at which dose and how many times

Psilocybin 0.7 g