Do treated psychiatric patients become later community cases? A prospective cohort study.

BACKGROUND: There have been few attempts to link two aspects of psychiatric epidemiology, severe disorder and milder 'common' mental disorder, by ascertaining whether subjects who have received psychiatric treatment for major disorders are identified later in epidemiological community surveys. METHODS: Subjects were from a national birth cohort study and had been followed prospectively from childhood to middle age, with concurrent information on treatment from psychiatric facilities. In two successive prevalence surveys of milder disorder at 36 and 43 years, the association between earlier treatment and being a later community case was examined RESULTS: Among 102 subjects who had been treated patients up to age 35 years, 52 (51%) were identified as definite community cases (36, 35%) or subthreshold cases (16, 16%) at either one or both later points. The proportion of community subjects who were previous psychiatric patients increased systematically from community non-cases, through subthreshold cases on one or both occasions, definite cases on one occasion, to definite cases on both occasions. CONCLUSIONS: About half of subjects who have received treatment from psychiatric facilities remain with persistent symptoms such as to identify them as definite or subthreshold cases of milder common mental disorder some years later.