How Diagnostic Concepts of Schizophrenia Differ

Abstract

Nine different systems used for diagnosing schizophrenia were applied to a sample of patients (272) from 2 geographical catchment areas who were hospitalized for the first time in their lives for functional psychiatric illness. The size and composition of the groups diagnosed as schizophrenic by each set of criteria were then compared with respect to 5 clinical variables hypothesized to be important for differentiating the diagnostic systems. All data were collected with structured interviews of demonstrated reliability. Several of the variables tested distinguished schizophrenics diagnosed by some systems from those considered schizophrenic by other systems and from those patients in the sample not considered schizophrenic by any system. High levels of delusions of passivity characterized the patients classified as schizophrenic by 3 systems: Schneider, Langfeldt and the Flexible System. High psychosis scores characterized the patients considered schizophrenic by the New Haven Schizophrenia Index. Increased chronicity and low levels of affective symptoms characterized the patients considered schizophrenic by the Feighner criteria. Poor work and social function characterized the patients considered schizophrenic by the hospital physician using DSM-II [Diagnostic and Statistical Manual of Mental Disorders II] guidelines. The various systems for diagnosing schizophrenia have both characteristic differences and overlap.