The diagnosis of schizophrenia: a review of onset and duration issues

The diagnosis of schizophrenia remains a topic of continuing dialogue both within the United States and internationally, as witnessed by the numerous revisions to the Diagnostic and Statistical Manual (i.e., DSM-I, DSM-II, DSM-III, and DSM-III-R) and the International Classification of Diseases (i.e., ICD-9, and ICD-10). At issue is how best to characterize patients suffering the debilitating symptoms and chronicity associated with the disease and, at the same time, arrive at a diagnosis that has specific clinical utility and can be reliably assessed. The purpose of the following report is to review three issues associated with the diagnosis of schizophrenia: the role of prodromal and residual symptoms, the duration of psychotic symptoms, and the 6-month versus 1-month time criterion. Our general recommendation, based on extant studies providing data related to various facets of the issues under debate, is to use diagnostic criteria that are consistent with the international diagnostic system. However, final decisions will depend on the outcome of the ongoing DSM-IV field trials.