100 YEARS OF SCHIZOPHRENIA - A METAANALYSIS OF THE OUTCOME LITERATURE

Objective: This study was undertaken to assess the twentieth-century l iterature on outcome in schizophrenia for historical trends that might be associated with changes in diagnostic and therapeutic practice and to test the hypothesis that both improved biological treatment and ch anges in diagnostic criteria have influenced outcome. Method: Meta-ana lysis of the international literature on outcome in schizophrenia or d ementia praecox from 1895 to 1992 identified 821 studies; 320 of these , with 51,800 subjects in 368 cohorts, met the inclusion criteria for the study. Results: Only 40.2% of patients were considered improved af ter follow-ups averaging 5.6 years (range=1-40). Outcome was significa ntly better when patients were diagnosed according to systems with bro ad criteria (46.5% were improved) or undefined criteria (41.0% were im proved) rather than narrow criteria (27.3% were improved). The proport ion of patients who improved increased significantly after mid-century (for 1956-1985 versus 1895-1955, 48.5% versus 35.4%), probably reflec ting improved treatment as well as a broadened concept of schizophreni a. However, in the past decade, the average rate of favorable outcome has declined to 36.4%, perhaps reflecting the re-emergence of narrow d iagnostic concepts. Conclusions: Overall, less than half of patients d iagnosed with schizophrenia have shown substantial clinical improvemen t after follow-up averaging nearly 6 years, Despite considerable gains in improvement rates after mid-century, there has been a decline sinc e the 1970s. These historical changes probably reflect improved treatm ent, shifts in diagnostic criteria, and selection bias related to chan ges in health care.