Clinical courses of schizophrenia

Schizophrenia is a complex disorder, characterized by molecular, neuroendocrine, and behavioral alterations as well as gene-environment interactions. This article summarizes key facts on the diagnosis, long-term course and neurocognitive deficits of schizophrenia. Due to the heterogeneity of schizophrenia with regard to symptomatology, illness manifestations, course and outcome, the focus of attention has shifted from diagnostic categories to endophenotypes which are hoped to characterize distinct subtypes of schizophrenia more appropriately than the diagnostic classification systems. The systems approach aims to assess the complexity and multiple dynamics of biological systems to explain endophenotypes of schizophrenia and their associations with susceptibility genes. Data presented in this paper support the view that looking for associations between neurocognitive endophenotypes and susceptibility genes might be a promising approach for future research to elucidate the heterogeneity of schizophrenic spectrum disorders.