Effects of Adolescent Synaptic Pruning (SPA PET)

Inclusion Criteria:

• Males or females between 18-26 years of age, AND currently enrolled in the Parent Project (R01MH067924)

Exclusion Criteria: (these exclusion criteria are outlined in the Parent Project)

• Head injury with loss of consciousness over an hour.
• A vision problem or eye movement problem (such as lazy eye, double vision, blurred vision, or color blindness).
• A learning disability and/or ever had an Individualized Education Plan (IEP) in school.
• Significant neurological or metabolic illness: Epilepsy, Meningitis, Encephalitis, Diabetes, Huntington's disease.
• Diagnosed with a psychiatric disorder.
• Participants with, or with a first degree relative, having a DSM IV Axis l psychiatricdisorder.
• Metal implants or ferromagnetic objects contained within the body which may interfere with the MRI scan (but not limited to, those with a pacemaker, presence of metallic fragments near the eyes or spinal cord, or cochlear implant.) Dental fillings do not present a risk for MRI. If there is a possibility of metal being present in the participant's body, the participant will be excluded from the study.
• Weight more than 250 pounds.
• Claustrophobia or uncomfortable in small spaces.
• <70% on the Achenbach scale (either from Youth Self Report (YSR) or Adult Self Report (ASR)).
• IQ < 80 or IQ > 130.
• Pregnancy or lactation, lack of effective birth control during 15 days before the scans.
• Currently employed as radiation worker; or participation in radioactive drug research protocols within the previous year such that the total cumulative annual radiation dose (i.e., from participation in the previous radioactive drug study [studies] and this study) would exceed the radiation dose limits specified in the FDA regulations (i.e., 21 CFR 361.1) that govern the research use of [C-11]UCB-J
• History of drug or alcohol abuse (from parent study eligibility).