Natural course of schizophrenic disorders: a 15-year followup of a Dutch incidence cohort.

Data are presented on the 15-year natural course of schizophrenia and other nonaffective functional psychoses in a cohort of 82 first-contact cases from a circumscribed area in the Netherlands. The subjects were suffering from functional psychosis with International Classification of Diseases-Ninth Revision (ICD-9) diagnoses 295, 297, or 298.3-9 (broad definition of schizophrenia) on entry. Standardized assessments of psychopathology, psychological impairments, negative symptomatology, social disability, and use of mental healthcare were used. The study reveals a pattern of chronicity and relapses with a high risk of suicide: Two-thirds of the subjects had at least one relapse and after each relapse 1 of 6 subjects did not remit from the episode; 1 of 10 committed suicide; and 1 of 7 had at least one episode with affective psychotic symptoms that started on average 6 years after the onset of the schizophrenic disorder. Diagnoses were reclassified in five patients, according to DSM-III-R criteria for a bipolar disorder. The predictive power--in terms of time in psychosis and in partial or full remission--of demographic, illness, and treatment variables at onset of the illness was very limited. Insidious onset and delays in mental health treatment are risk factors that predict a longer duration of first or subsequent episodes. The importance of mental health treatment in regard to outcome is probably subject to change because an early warning and intervention strategy could prevent further damage and deterioration. Our data support the need for an adequate relapse prevention program as a priority for our mental health services.