Heterogeneity in incidence rates of schizophrenia and other psychotic syndromes

ABSTRACT

CONTEXT Convention suggests uniformity of incidence of schizophrenia and other psychoses; variation would have implications for their causes and biological characteristics. OBJECTIVE To investigate variability in the incidence of psychotic syndromes in terms of place, ethnicity, age, and sex. DESIGN Three-center, prospective, comprehensive survey of clinically relevant first-onset psychotic syndromes over a 2-year period (1997-1999). Census data provided the denominator. SETTING Southeast London, Nottingham, and Bristol, England. PARTICIPANTS One million six hundred thousand person-years yielded 568 subjects aged 16 to 64 years with clinically relevant psychotic syndromes. MAIN OUTCOME MEASURES The World Health Organization Psychosis Screen and the Schedules for Clinical Assessment in Neuropsychiatry to classify, blind to ethnicity, all DSM-IV psychotic syndromes and the subclasses of schizophrenia, other nonaffective disorders, affective disorders, and substance-induced psychosis.