A prominent theory of psychedelics is that they increase brain entropy. Thirteen studies have evaluated psychedelic effects on fMRI brain entropy, each applying a distinct measure. Here we evaluated these metrics in an independent 28-participant healthy cohort with 121 pre- and post-psilocybin fMRI scans. We assessed relations between brain entropy and objective and subjective psychedelic drug...
Patients with chronic cluster headache (CCH) suffer from poor sleep, which may impact their brain microstructure and parenchymal clearance of waste products. Psilocybin has shown promise for the treatment of CCH and has been linked to increased neuroplasticity with possible influences on brain microstructure. To investigate the effects of psilocybin on sleep, brain water diffusivity, and...
A key distinction among clinical trials on psilocybin treatments, for example, those targeting depression, has been whether the psilocybin dosing session is combined with bona fide psychotherapy or with what is referred to as “psychological support” (1-3). The most developed model of psychological support is the Compass Psychological Support Model (CPSM; 1). Kirlić and colleagues specifically...
Psilocin, the active metabolite of psilocybin, is a psychedelic and agonist at the serotonin 2A receptor (5-HT2AR) that has shown positive therapeutic effects for brain disorders such as depression. To elucidate the brain effects of psilocybin, we directly compared the acute effects of 5-HT2AR agonist (psilocybin) and antagonist (ketanserin) on cerebral blood flow (CBF) using pseudo-continuous...
The serotonergic psychedelic psilocybin acutely induces changes in emotional states. However, it remains unresolved whether psilocybin acutely modulates amygdala reactivity to emotions, a brain region critically involved in emotion processing. Using functional magnetic resonance imaging (fMRI), we examined in 26 healthy individuals whether amygdala responses to angry, fearful and neutral faces...
A prominent theory of psychedelics is that they increase brain entropy. Twelve studies have evaluated psychedelic effects on fMRI brain entropy quantifications, no findings have been replicated. Here we evaluated these metrics in an independent 28-participant healthy cohort with 121 pre- and post-psilocybin fMRI scans. We assessed relations between brain entropy and plasma psilocin, brain...
Our findings suggest that the acute perceptual psychedelic effects induced by psilocybin may stem from drug-level associated decreases in the occurrence and duration of lateral and medial frontoparietal connectivity motifs. We apply and argue for a modified approach to modeling eigenvectors produced by LEiDA that more fully acknowledges their underlying structure. Together these findings...
Background Psilocybin-induced mystical-type experiences are associated with lasting positive psychological outcomes. Recent studies indicate that trait mindfulness is increased 3 months after psilocybin intake, preceded by decreases in neocortical serotonin 2A receptor (5-HT 2A R) binding. However, the association between psilocybin-induced mystical-type experiences and subsequent changes in...
Psychedelic drugs such as psilocybin have shown substantial promise for the treatment of several psychiatric conditions including mood and addictive disorders. They also have the remarkable property of producing persisting positive psychological changes in healthy volunteers for at least several months. In this study (NCT03289949), 35 medium-high doses of psilocybin were administered to 28...
Abstract Background Psilocin, the neuroactive metabolite of psilocybin, is a serotonergic psychedelic that induces an acute altered state of consciousness, evokes lasting changes in mood and personality in healthy individuals, and has potential as an antidepressant treatment. Examining the acute effects of psilocin on resting-state dynamic functional connectivity implicates network-level...
Psychedelic drugs such as psilocybin are under investigation for the treatment of several psychiatric conditions. They also have the remarkable property of producing persisting positive psychological changes in healthy volunteers for at least several months. In this study, 35 medium-high doses of psilocybin were administered to 28 healthy volunteers (12 females). By the end of the dosing day,...
The emerging novel therapeutic psilocybin produces psychedelic effects via engagement of cerebral serotonergic targets by psilocin (active metabolite). The serotonin 2A receptor critically mediates these effects by altering distributed neural processes that manifest as increased entropy, reduced functional connectivity (FC) within discrete brain networks (i.e., reduced integrity) and increased...