Psilocybin microdosing does not affect emotion-related symptoms and processing: A preregistered field and lab-based study
Journal of Psychopharmacology – December 17, 2021
Source: OpenAlex
Summary
Despite popular belief, a rigorous double-blind, placebo-controlled crossover study revealed that microdosing the hallucinogen psilocybin for three weeks did not alleviate anxiety or depression symptoms. This research in clinical psychology, exploring how psychedelics, specifically this chemical synthesis alkaloid, influence behavior and affect, found no significant changes in emotion processing. The findings challenge anecdotal reports suggesting psilocybin's broad benefits, indicating its neurotransmitter receptor influence might not translate to these particular psychological improvements in a microdosing context. Psychiatry may need to re-evaluate common assumptions.
Abstract
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.