Epidemiology of long-term functional psychosis in three different areas in Stockholm County

This study is the first in a series investigating different aspects of living conditions and care utilization in a total population with long-term functional psychoses (LFP). The study cohort (n = 302) was defined as people that: were aged 18-64 years, were affected by a nonorganic psychosis continuously during at least 6 months, showed psychotic features or residual symptoms during 1984, and had their home address in the study area during 1984. The study area consists of one rural and one suburban municipality, and one urban parish (57,035 inhabitants aged 18-64 years). The LFP concept used shows a high interrater reliability (kappa = 0.93). The one-year prevalence in the rural, suburban and urban areas was 3.4, 5.6 and 6.6 per 1000 respectively, thus producing a gradient from the rural to the urban areas. The prevalence of schizophrenia (DSM-III) was 2.6, 3.8 and 5.0 per 1000 respectively. The other diagnoses covered by the LFP concept (paranoia, major affective disorder with psychotic features, and psychotic disorder not elsewhere classified) showed the same gradient, with the exception of paranoia, which showed a lower rate in the urban area. The prevalence of schizophrenia was higher among males, while for paranoia the prevalence was higher among females.