First-admission schizophrenic patients in northern Norway, 1980-95: Sex differences in diagnostic practice

Several studies of first-contact incidence studies of schizophrenia suggest a significant excess of males. We wanted to investigate the clinical diagn ostic process in a cohort of first-episode schizophrenic patients to search for possible implications for epidemiologic research. All first-ever admit ted schizophrenic patients in the two northernmost counties in Norway (Trom s and Finnmark, covering 250,000 inhabitants) with three or more admissions during the period 1980-95 (60 females and 91 males with a total of 1326 ad missions) were included in the study. Norway shifted diagnostic system from ICD-8 to ICD-9 in 1987. The impact of this shift on the diagnostic process was also studied. Our study shows that females had a significantly longer period than did males from first admission until the first diagnosis of sch izophrenia (2.6 years and 3.4 admissions versus 1.6 years and 2.3 admission s). Thirty-three per cent of the females received the diagnosis at first ad mission, and 47% of the males. Females received the diagnosis of personalit y disorder significantly more often than males before the first diagnosis o f schizophrenia. The schizophrenia diagnosis remained unchanged in 79% of t he cases; stability was even higher (90 %) for those diagnosed at first adm ission. Our conclusion is that diagnostic practice in the course of schizop hrenia showed a significant sex difference, both in diagnostic distribution and in latency period before first schizophrenia diagnosis. The total late ncy period decreased after the introduction of new guidelines in 1987, but the sex difference in latency period persisted.