Course of Schizophrenia: What Has Been Learned from Longitudinal Studies?

Abstract

Understanding the course of schizophrenia is essential to improve pro- phylaxis, early diagnosis, diagnostic validity, and prognosis. While the majority of the longitudinal studies of schizophrenia report that 50–70% of patients have a chronic, generally persistent course of illness, the rest of the patients present with a heterogeneous course. Furthermore, there are no clear course predictors at the time of the initial diagnosis. In this chapter we discuss likely contributors to the reported course heterogeneity of schizophrenia. Schizophrenia longitudinal studies are based on heterogeneous patient samples, using different inclusion criteria to define the type and severity of the disease. Different diagnostic approaches as described by Kraepelin, Bleuler, Schneider, Conrad and DSM, amongst others, have been used over time. The implications of different diagnostic systems on course and outcome are discussed.