Human brain changes after first psilocybin use

Area of Science:

• Neuroscience
• Psychopharmacology
• Neuroimaging

Background:

• Psychedelics profoundly impact brain function and behavior, but their potential for enduring anatomical and functional changes remains under-explored.
• Understanding these long-term effects is crucial for therapeutic applications and safety assessments.

Purpose of the Study:

• To investigate enduring anatomical and functional brain changes following a single high dose of psilocybin in psychedelic-naive individuals.
• To explore the relationship between neuroimaging findings and psychological outcomes over a one-month period.

Main Methods:

• An exploratory, placebo-controlled, within-subjects study involving 28 healthy, psychedelic-naive participants.
• Utilized electroencephalography (EEG), magnetic resonance imaging (MRI), and diffusion tensor imaging (DTI) before and up to one month after psilocybin administration.
• Assessed cognitive flexibility, psychological insight, and well-being at one-month post-dose.

Main Results:

• Psilocybin (25 mg) administration led to increased cognitive flexibility, psychological insight, and well-being at one month.
• Diffusion tensor imaging revealed decreased axial diffusivity in prefrontal-subcortical tracts, correlating with reduced brain network modularity.
• Increased cortical signal entropy (EEG) at 1-2 hours post-dose predicted improved one-month well-being, mediated by next-day psychological insight.

Conclusions:

• A single high dose of psilocybin can induce lasting neuroanatomical and functional brain changes, alongside significant psychological benefits.
• Decreased brain network modularity was associated with reduced psychological well-being, consistent with findings in depression.
• Cortical signal entropy post-psilocybin may serve as a predictor for long-term psychological outcomes.