Participants with schizophrenia or schizoaffective disorder who are competent to participate in the informed consent process and provide written informed consent will be enrolled into the study. Participants will undergo a psychiatric evaluation, which will include the ascertainment of demographic information, past psychiatric and treatment history, and Structured Clinical Interview for DSM-IV (SCID; First et al, 1997) diagnostic interviews. A best estimate diagnostic approach will be utilized in which information from the SCID is supplemented by information from family informants, previous psychiatrists, and medical records to generate a diagnosis.