Depression in the family physician's office: what the psychiatrist needs to know: the Michigan Depression Project.

A rapidly growing body of research suggests that depression in primary care may differ from that in psychiatry in its nature, severity, comorbidity, and responsiveness to treatment. The Michigan Depression Project is a long-term series of studies designed to explore the twin assumptions that depressed primary care patients are similar to depressed psychiatric patients and that identical treatment will benefit both groups. Major findings are (1) criterion-based diagnosis of major depressive disorder in primary care includes many patients with mild depression and little to no impairment; (2) the onset of depression among family practice patients-but not psychiatric patients-is usually preceded by a severe life event; (3) in primary care, outcome for patients with undetected depression appears to be comparable to that for those with detected depression; and (4) family physicians appear to employ historical cues in assigning the diagnosis of depression to distressed and impaired patients. The results of the Michigan Depression Project and the recent work of other researchers suggest that the challenges facing primary care physicians in the diagnosis and treatment of depressed patients are daunting. These challenges lead to a set of consultative skills and behaviors on the part of psychiatrists that may be different than generally expected. One-time, stand-alone psychiatric consultations are often needed, because neither the primary care physician nor the patient desires the psychiatric care to be "carved out" from the continuing care of a set of chronic problems. Future intervention studies should compare subgroups of patients who appear most in need of treatment (on the basis of functional impact) with those who are mildly depressed and barely meet diagnostic criteria. These studies will help primary care physicians focus their energies and therapies where they will have the most benefit in treating what is clearly a common and important, but still poorly understood, problem in primary care medical practice.