Rationale: Researchers sought to understand how cannabis use influences brain activity involved in maintaining social relationships, understanding other perspectives, and predicting behavior—characteristics associated with Theory of Mind (ToM).

Method: The study evaluated 1000 participants between the ages of 22 and 37. Researchers gave subjects seven Theory of Mind (ToM) tasks while measuring their brain activity. From these data, they found areas of the brain that were active during the ToM tasks and compared them in users and non-users.

Results: Regular cannabis use reduced neural processing related to ToM, the capacity to recognize and understand other perspectives. Recent cannabis use also impaired brain functioning tied to ToM.

Meaning: Recent or long-term use dampens the brain activity necessary for understanding other perspectives. People may think of cannabis as a pro-social drug, but evidence shows it disrupts social processing skills.