The prognosis of depression in the elderly.

Controversy prompted a systematic and critical review of original research articles to determine the prognosis of depression in the elderly. A search of three computer databases for articles published from January 1980 to May 1989 and of the bibliographies of articles located revealed 10 reports, involving 990 subjects, that met the following inclusion criteria: original research, published in English or French since 1950, sample of at least 25 patients, inclusion of only patients over 60 years, mean follow-up period of 1 year or more and description of the patients' mental state during follow-up. The methods and study designs were then assessed with the use of the criteria for prognostic studies established by McMaster University Health Sciences Centre, Hamilton, Ont. All of the studies had serious, multiple flaws. Nevertheless, when the results were combined it appeared that at least 60% of the patients remained well or had relapses with recovery (mean follow-up 31.9 months); up to 25% remained continuously ill. Physical illness, cognitive impairment and severe depressive symptoms were frequently related to poor prognosis; most of the social factors studied were not related to prognosis. Future studies must pay attention to methods and design, particularly the composition of study populations, the assessment of outcomes and the control of extraneous prognostic factors.