Minimizing Doses of Antipsychotic Medication in Older Patients With Schizophrenia.

Inclusion Criteria: * Age of 50 and older * DSM-IV/SCID diagnosis of schizophrenia, schizoaffective disorder, schizophreniform disorder, delusional disorder, or psychotic disorder NOS * Having been treated with oral risperidone at a steady dose of ≥ 2 mg/day, or with olanzapine at a steady dose of ≥10 mg/day, for at least 12 months. Exclusion Criteria: * Incapacity to provide consent to psychiatric treatment * Participation in this study would result in exceeding the annual radiation dose limits (20 mSv) for human subjects participating in research studies. * Substance abuse or dependence (within past six months) * Positive urine drug screen * Positive serum pregnancy test at screening or positive urine pregnancy test before PET scan * Having taken more than one dose of antipsychotics other than risperidone or olanzapine during the 7 days preceding the PET scan * History of treatment with long-acting (depot) neuroleptic antipsychotic medication or Risperdal Consta within 12 months of PET scanning * Metal implants or a pace-maker that would preclude the MRI scan * Addition of or change in dose of antidepressants, valproic acid, lithium, carbamazepine, or lamotrigine for mental health reasons within 12 months of screening * History of head trauma resulting in loss of consciousness \> 30 minutes that required medical attention * Unstable physical illness or significant neurological disorder including a seizure disorder * Size of head, neck, and body being unable to fit PET an…