Consequences of Marijuana Use in HIV-infected Youth

Inclusion Criteria: * Age 21 years 0 days - less than28 years 364 days * Currently treated with stable ART and no ART changes for \>6months. * Willingness to participate in CASI questionnaire of self-reported substance use * Documented behavioral transmission of HIV infection based on CLIA approved HIV antibody/antigen based testing method in medical record -HIV diagnosis greater than or equal to years. Viral load LESS THAN 50 COPIES/ML for the past 6 months. -- Patients may have had single blips in viral load to greater than 50 but less than 1000 copies/ml within the year prior to screening. * Current Substance profile by chart review or phone screening: * Marijuana use defined as marijuana use by any route at least 3 times per week in the absence of tobacco. N= 20. * Tobacco use only based on report of regular (at least 3 times per week smoking). N=24 * Tobacco plus marijuana use defined as regular smoking and marijuana (at least 3 times per week) N =7 * No substance use of any type (alcohol, tobacco, marijuana or other recreational drugs in the past 90 days). N = 10 * Able to provide written informed consent in English and to adhere to protocol schedule Exclusion Criteria: * History of AIDS defining illness * Pregnancy at any time during the study * Use of substances that would interfere with the ability to complete the study * History of significant cognitive or motor impairment or other chronic condition that would interfere with the ability to complete the study and impact neurocognitive testing * Acute psychiatric symptoms (e.g. suicidality, mania, psychosis or severe depression) * Other neurological disorder (e.g. multiple sclerosis, seizure disorder, etc.) requiring ongoing treatment or active outpatient evaluation * Severe mental illness (requiring antipsychotic or mood stabilizing medications and/or inpatient hospitalization in past year) * History of CNS infection (AIDS opportunistic (e.g. toxoplasmosis) or non-opportunistic (bacterial meningitis) with lasting or permanent neurological sequelae) * Underlying and/or uncontrolled medical illnesses that may result in chronic inflammation , (e.g. SLE or autoimmune disease) as determined by the PI * Nursing mothers * Unable to read and write in English