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

Area of Science:

• Neuroscience
• Psychopharmacology
• Clinical Psychology

Background:

• Anecdotal reports suggest microdoses of psychedelics can alleviate depression, anxiety, and stress.
• Psilocybin research at higher doses indicates potential mechanisms involving emotion and interoceptive processing modulation.

Purpose of the Study:

• To investigate if psilocybin microdoses affect self-reported interoceptive awareness.
• To determine if repeated microdosing over three weeks modulates emotion processing and reduces anxiety and depression symptoms.

Main Methods:

• A double-blind, placebo-controlled, within-subject crossover design was employed.
• Participants self-administered psilocybin microdoses or placebo every third day for three weeks.
• Assessments included the Multidimensional Assessment of Interoceptive Awareness Questionnaire, emotional go/no-go task, and Depression Anxiety Stress Scale.

Main Results:

• Confirmatory analyses showed no significant effect of psilocybin microdosing on emotion processing or anxiety and depression symptoms compared to placebo.
• Exploratory analyses indicated no impact on self-reported interoceptive awareness.
• While depression and stress symptoms reduced in the first block, participants broke blind in the second block, and expectations had no effect.

Conclusions:

• Psilocybin microdosing did not demonstrate efficacy in this study for improving emotion processing or reducing anxiety and depression symptoms.
• Further investigation in a substance-naïve population with clinical anxiety and depressive symptoms is warranted to validate potential benefits.