Time trends in first admission rates for schizophrenia and other psychotic disorders in Taiwan, 1998-2007: a 10-year population-based cohort study

Abstract

Purpose: To examine the trend in annual first admission rates for psychotic disorders as a whole as well as individual psychotic disorders in Taiwan from 1998 to 2007, and influences of age, sex, and geographic region on the trend.

Method: Using the inpatient claims records in the National Health Insurance Research Database, we estimated the yearly first admission rates for schizophrenia and other psychotic disorders, including voluntary (1998-2007) and involuntary (2004-2007) admissions. Both narrow and broad definitions of psychotic disorders were examined.

Results: While involuntary first admission rates were stable, a crescendo-decrescendo change in voluntary first admission rates for psychotic disorders was observed, peaking in 2001. The increase from 1998 to 2001 was closely associated with health insurance expansion. Before 2001, the voluntary first admission rates in males aged 15-24 were underestimated as military personnel records were not included in the database. From 2001 to 2007, voluntary first admissions for psychotic disorders decreased 38%; the decrease could not be accounted for by the mild diagnostic shifts away from schizophrenia to affective psychosis or substance-induced psychosis. During the entire observation period, first admission rates for schizophrenia decreased 48%, while affective psychosis increased 84%. Gender disparities in the first admission rates gradually diminished, but geographic disparities persisted.

Conclusions: First admission rates for psychosis significantly reduced in Taiwan between 1998 and 2007, mainly driven by the reduced hospitalization risk for schizophrenia. Special attention should be paid to the increased hospitalization for other types of psychotic disorders (especially affective psychosis) and the unresolved geographic disparities.

Keywords: Epidemiology; First admission; Gender disparity; Psychotic disorders; Schizophrenia.