Cannabis, HIV and Mental Processing Systems

This study is examining how cannabis use affects brain function and mental processing in people living with HIV compared to HIV-negative individuals. Researchers will use brain MRI, cognitive tests, and other measures to understand how cannabis — with or without HIV — affects the brain over time. **You may be eligible if:** - You are between 18 and 70 years old - If you are HIV-positive: you have had a confirmed HIV diagnosis for about 1 year, have been on stable antiretroviral therapy for at least 3 months, and your viral load is well-controlled - If you are HIV-negative: you have confirmed negative HIV status - You have completed at least 9 years of education - You are willing to have your cannabis use confirmed through interview and urine testing - You are able to undergo an MRI scan **You may NOT be eligible if:** - You have a history of stroke, significant head injury, or developmental learning disability - You have uncontrolled bipolar disorder or schizophrenia - You have a current substance use disorder other than cannabis - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.