One dose of Psilocybin modulates Brain Activity among Depressive patients : Preliminary Neuroimaging Results from the PSILODAC Study
M. Pastre, F. Pereira, T. Gibert, A. Giron, B. Goemare, E. Olié, P. Courtet, J. Lopez-Castroman, I. ConejeroIntroduction
Treatment-resistant depression (TRD) remains a major clinical challenge, with limited efficacy of available therapies. Psilocybin, a serotonergic psychedelic, has shown promising antidepressant effects. As recent studies have shown altered default mode network activity following psilocybin administration, further neuroimaging research in clinical populations is needed to clarify its mechanisms of action and the neural networks associated with symptom improvement in depression.
Objectives
To investigate whether the antidepressant effects of psilocybin are associated with changes in resting-state brain activity and to assess the feasibility of conducting psilocybin trials in a French clinical population.
Methods
Patients meeting DSM-IV criteria for moderate to severe TRD underwent two fMRI sessions 2 days before and 5 days after a single oral psilocybin administration (25 mg). Amplitude of Low Frequency Fluctuations (ALFF) and regional homogeneity analyses were conducted to identify changes in resting brain activity after psilocybin.
Results
Ten patients underwent the two fMRI sessions (8 women, 1 man; mean age 42.2 years). Resting-state analyses revealed increased ALFF signal in the right Ventro-Lateral Pre-Frontal Cortex (vlPFC) (Figure 1), the right Medial Pre-Frontal Cortex (mPFC) (Figure 2), and the left Inferior Parietal Lobule (IPL) (Figure 3) after psilocybin administration. Regional homogeneity analyses confirmed greater signal coherence in overlapping regions.
Image 1: Long description.