The Epidemiology and Descriptive and Predictive Validity ofDSM-IVDelusional Disorder and Subtypes of Schizophrenia

Objective: We studied the clinical and epidemiological features of DSM-IV delusional disorder and schizophrenia subtypes in a general population-based sample and investigated the descriptive and predictive validity of these diagnoses. Method: The study was based on a nationally representative survey of 8,028 persons aged thirty years or over from Finland. DSM-IV psychotic disorders were diagnosed using the SCID-I interview and/or case note data. Lifetime severity of symptoms and course and outcome of the disorder were assessed using the Major Symptoms of Schizophrenia Scale. Based on information from the interview, case notes, and health care registers, we assessed current and lifetime treatment contacts, hospitalizations, and antipsychotic medication use. Results: The prevalences were 0.18% (95% CI 0.11-0.30) for delusional disorder; 0.24% (95% CI 0.15-0.37) for paranoid, 0.42% (95% CI 0.30-0.59) for undifferentiated and 0.16% (95% CI 0.09-0.27) for disorganized schizophrenia. Both delusional disorder an...