In the first study, published today in
Proceedings of the National Academy of Sciences (
PNAS), 30 healthy volunteers had psilocybin infused into their blood while inside
magnetic resonance imaging (MRI) scanners, which measure changes in brain activity. The scans showed that activity decreased in "hub" regions of the brain – areas that are especially well-connected with other areas.
The second study, due to be published online by the
British Journal of Psychiatry on Thursday, found that psilocybin enhanced volunteers' recollections of personal memories, which the researchers suggest could make it useful as an adjunct to psychotherapy.
The function of these areas, the medial prefrontal cortex (mPFC) and the posterior cingulate cortex (PCC), is the subject of debate among neuroscientists, but the PCC is proposed to have a role in consciousness and self-identity. The mPFC is known to be hyperactive in depression, so psilocybin's action on this area could be responsible for some antidepressant effects that have been reported. Similarly, psilocybin reduced blood flow in the hypothalamus, where blood flow is increased during cluster headaches, perhaps explaining why some sufferers have said symptoms improved under psilocybin.
"Previous studies have suggested that psilocybin can improve people's sense of emotional wellbeing and even reduce depression in people with anxiety. This is consistent with our finding that psilocybin decreases mPFC activity, as many effective depression treatments do. The effects need to be investigated further, and ours was only a small study, but we are interested in exploring psilocybin's potential as a therapeutic tool."
MedicalXpress