title: Epidemiology of psychosomatic disorders in schizophrenic patients: methodological issues.
abstract: The value of an epidemiological study investigating the prevalence of certain somatoform diseases in schizophrenic patients can be strengthened by attention to the following methodological principles: (1) sufficient size of sample; (2) representativeness of sample, controlling if possible such variables as age range, inpatient or outpatient status, ward population or milieu and cultural aspects; (3) study of control groups in same milieu with other psychiatric diagnoses; (4) clear specification of diagnostic criteria employed; (5) establishment of interrater reliability concerning psychiatric diagnosis, patient historical data or medical record information.
mesh_terms: D001172:Arthritis, Rheumatoid / Q000453:epidemiology; D001249:Asthma / Q000453:epidemiology; D003430:Cross-Sectional Studies; D006801:Humans; D009450:Neurodermatitis / Q000453:epidemiology; D010437:Peptic Ulcer / Q000453:epidemiology; D011602:Psychophysiologic Disorders / Q000453:epidemiology* / Q000523:psychology; D012559:Schizophrenia / Q000150:complications*; D012565:Schizophrenic Psychology