Investigating the Neural Correlates of Cognitive Function in Psychosis Patients and Non-Psychiatric Controls With Cannabis Use

This study is using brain scans (MRI) to investigate how regular cannabis (marijuana) use affects thinking and brain function in people with psychosis compared to people without a psychiatric diagnosis. **You may be eligible if...** - You use cannabis heavily (at least weekly for six or more months) or have a cannabis use disorder - You have an IQ of 75 or above - You are an outpatient receiving stable doses of medication for at least 2 months and are clinically stable (psychosis patient arm) - OR you are a non-psychiatric adult who uses cannabis heavily (control arm) **You may NOT be eligible if...** - You use other substances besides cannabis, nicotine, or caffeine - You have MRI contraindications (e.g., metal implants) - You have current suicidal or homicidal thoughts - You have had a head injury requiring hospitalization - You are under 16 years old Talk to your doctor to see if this trial is right for you.