Brief interventions to prevent depression in older subjects: a systematic review of feasibility and effectiveness

This systematic review proposed to explore the feasibility and effectiveness of brief interventions to prevent depression in older subjects. Computer databases were searched for potentially relevant articles published up until August, 2007. The bibliographies of relevant articles were searched for additional references and all the retrieved articles were screened to meet the following five inclusion criteria: original research, subjects mean age 40 years or more, controlled trial of a brief (<12 weeks) intervention to prevent depression, determination of depression status 6 months or more after enrolment, and use of an acceptable definition of depression. To examine feasibility, study enrolment, completion, and compliance rates were tabulated. To examine effectiveness, differences in depression symptom outcome scores or, when possible, absolute risk reductions (ARR) and relative risk reductions (RRR) for depression were tabulated. Fourteen trials were located. All were trials of brief psychosocial interventions. Many had one or more methodological limitations. Study enrolment rates were 21%-100% (median 45%-49%); completion rates were 53%-100% (median 85%); compliance rates were 29%-100% (median 80%). Eight trials had positive results. In three trials there were significant differences in depression symptom outcome scores favoring the intervention group; in eight trials, ARRs were -17% to 45% (median 6%); RRRs were -125% to 71% (median 33%). It seems that some types of brief psychosocial interventions have the potential to prevent depression in older subjects. Guidelines to improve the quality of future trials are proposed.