Imaging the Effects of Serotonin 2A Receptor Modulation on Synaptic Density in Treatment-resistant Depression (SYNVEST)

Psilocybin, the chemical component of "magic mushrooms", has been administered with psychotherapy in several randomized clinical trials (RCTs) showing large and sustained antidepressant effects. In healthy volunteers, the psychedelic effects of psilocybin have been shown to be blocked by administration of certain medications such as risperidone. The purpose of this study is to use an established SV2A radiotracer produced at our Centre to determine the feasibility of integrating PET imaging in to psilocybin trials. The preliminary imaging data will assess whether psilocybin's antidepressant effects are related to changes in synaptic density in adults with TRD, and whether any changes in synaptic density are associated with psilocybin's actions on the 5-HT2AR.