An Investigation of Mechanisms That Underly Paranoia in Behaviour and Brain That Can Inform Clinical Diagnoses That Include Paranoid Symptoms.

The study team is studying how delta-9-tetrahydrocannabinol (THC) - the component of cannabis that is responsible for "getting people feeling high" - influences how people think about the behaviour of others and a variety of other experiences. The study team is investigating these processes in healthy adults. The study team uses computer-based tasks and questionnaires to understand how people make conclusions about other people's intentions under different circumstances. In this study, the study team uses a placebo-controlled within-participant study design with three different conditions: (i) 1mg/ml THC administration, (ii) 2mg/ml THC administration, and (iii) placebo (Saline) administration, all via an intravenous IV. The study is within-participants, meaning that every participant will experience all three conditions. The study is double blind, meaning that neither the researcher nor the participant will know what condition they will be in on a given study visit. The sequence of conditions is balanced across participants.