Current or lifetime major DSM-IV Axis I disorder

Current or lifetime treatment (at least 6 months) with psychotropic medications for major psychiatric or neurological illness

Major or unstable medical illness that might impact safety of the subject in the study

Cannabis naive

IQ less than 85

Less than a high school diploma or its educational equivalent

Pregnancy or lactation

Major current or recent (\<6 weeks) psychosocial stressors.

Having a family member with psychosis

Current or lifetime major DSM-IV Axis I disorder

Current or lifetime treatment (at least 6 months) with psychotropic medications for major psychiatric or neurological illness

Major or unstable medical illness that might impact safety of the subject in the study

Cannabis naive

IQ less than 85

Less than a high school diploma or its educational equivalent

Pregnancy or lactation

Major current or recent (\<6 weeks) psychosocial stressors.

Probing the Cannabinoid System in Individuals With a Family History of Psychosis