Demography of paranoid psychosis (delusional disorder): a review and comparison with schizophrenia and affective illness.

This article reviews the demographic characteristics of paranoid psychosis or delusional disorder (DD) and compares them with those found for schizophrenia and affective illness. Delusional disorder constitutes between 1% and 4% of all psychiatric admissions, with an incidence of first admissions between 1 and 3/100,000 population per year. Like affective illness, but unlike schizophrenia, DD is predominantly an illness of middle to late adult life, usually occurring in persons who have been married. Like schizophrenia, but unlike affective illness, DD occurs more frequently in low socioeconomic classes and produces a poor chance for full recovery. Delusional disorder occurs more frequently than either schizophrenia or affective illness in immigrants. From a demographic perspective, DD closely resembles neither schizophrenia not affective illness.