Early detection of depression by primary care physicians.

The overall prevalence of depression is from 3.5% to 27%. The burden of suffering is high and includes death through suicide. In most cases treatment is effective, but important episodes of depression are being missed. To determine whether a brief, systematic assessment for the early detection of depression should be part of the periodic health examination we searched MEDLINE and the Science Citation Index for randomized controlled trials that evaluated the effectiveness of early detection of depression with a questionnaire. Seven instruments met our quality criteria; the Beck Depression Inventory, the Center for Epidemiologic Studies Depression Scale, the Zung Self-Assessment Depression Scale, the General Health Questionnaire, the Hopkins Symptom Checklist, the Mental Health Inventory and the Hospital Anxiety and Depression Scale. The four randomized controlled trials failed to provide adequate evidence of the benefit of routine screening. Early detection is difficult because of depression's natural history, the role of symptoms, the cultural diversity of Canada and how detection instruments have been developed. Depression deserves careful attention from primary care physicians; however, further research and development is required before the widespread routine use of any detection test can be recommended.