Phase I

The primary aim of this phase I mechanistic pilot study is to evaluate the effects of psilocybin on aspects of cognition in healthy adult volunteers. Up to 24 participants will receive a single dose of either psilocybin or inert placebo, and they will be asked to complete several computer-based behavioral tasks measuring features of learning, belief updating, and abstraction. Participants will also complete measures of subjective experience and expectancy, as well as semi-structured interviews at follow up, to assess whether experience correlates with behavior. This is a Voluntary Submission.