Journal of psychopharmacology | 2021
Lasting effects of a single psilocybin dose on resting-state functional connectivity in healthy individuals.
Abstract
BACKGROUND\nPsilocybin is a psychedelic drug that has shown lasting positive effects on clinical symptoms and self-reported well-being following a single dose. There has been little research into the long-term effects of psilocybin on brain connectivity in humans.\n\n\nAIM\nEvaluate changes in resting-state functional connectivity (RSFC) at 1\u2009week and 3\u2009months after one psilocybin dose in 10 healthy psychedelic-naïve volunteers and explore associations between change in RSFC and related measures.\n\n\nMETHODS\nParticipants received 0.2-0.3\u2009mg/kg psilocybin in a controlled setting. Participants completed resting-state functional magnetic resonance imaging (fMRI) scans at baseline, 1-week and 3-month post-administration and [11C]Cimbi-36 PET scans at baseline and 1\u2009week. We examined changes in within-network, between-network and region-to-region RSFC. We explored associations between changes in RSFC and psilocybin-induced phenomenology as well as changes in psychological measures and neocortex serotonin 2A receptor binding.\n\n\nRESULTS\nPsilocybin was well tolerated and produced positive changes in well-being. At 1\u2009week only, executive control network (ECN) RSFC was significantly decreased (Cohen s d\u2009=\u2009-1.73, pFWE\u2009=\u20090.010). We observed no other significant changes in RSFC at 1\u2009week or 3\u2009months, nor changes in region-to-region RSFC. Exploratory analyses indicated that decreased ECN RSFC at 1\u2009week predicted increased mindfulness at 3\u2009months (r\u2009=\u2009-0.65).\n\n\nCONCLUSIONS\nThese findings in a small cohort indicate that psilocybin affects ECN function within the psychedelic afterglow period. Our findings implicate ECN modulation as mediating psilocybin-induced, long-lasting increases in mindfulness. Although our findings implicate a neural pathway mediating lasting psilocybin effects, it is notable that changes in neuroimaging measures at 3\u2009months, when personality changes are observed, remain to be identified.