Most medical outpatient visits last 15 minutes or less [5], whereas visits to a mental health specialist typically last 30 minutes or longer [6]. Moreover, depression is but one, often subtle, on the item agenda in a medical encounter. During this encounter, the clinician must negotiate such competing priorities as acute symptoms, follow-up of chronic medical disorders, prescription refills, review of laboratory test results, and health maintenance. Medical patients with mental disorders typically present with fatigue, insomnia, pain, gastrointestinal symptoms, or other somatic symptoms rather than saying "I'm depressed" or "It must be my nerves" [7]. The presumed stigma of depression often inhibits explicit questioning, particularly if a trusting physician-patient relationship has not yet been established. However, clinicians overestimate patients' resistance; most patients are comfortable discussing psychosocial problems [8] and welcome questions about them [9, 10]. Problems with reimbursement include some insurers' rules that prohibit clinicians who are not mental health specialists from billing for treatment of psychiatric disorders, copayments, and restrictions on the number of visits.

Comorbid medical disorders camouflage depression by sharing somatic symptoms (for example, fatigue may be due to depression or to heart failure) or by providing patients with a reason to be depressed. In cases in which somatic symptoms overlap, special attention should be paid to depressed mood, anhedonia, feelings of guilt or worthlessness, or suicidal ideation. Somatic symptoms should not be discounted when depression is diagnosed unless the symptoms are clearly attributable to a physical disease (for example, insomnia in a patient with paroxysmal nocturnal dyspnea, memory loss in a patient with dementia, or anorexia in a patient with metastatic cancer).

"Wouldn't you be depressed if you had cancer? Human immunodeficiency virus disease? A stroke?" This all-too-common sentiment leads to the undertreatment of coexisting depression. The risk for major depression is increased by common disorders, including cancer; presence or treatment of cardiovascular disease (especially myocardial infarction or such interventions as bypass surgery or angioplasty); and central nervous system conditions, such as stroke, dementia, and Parkinson disease [11]. Depression causes more disability than do many chronic medical disorders [12, 13] and may worsen the affected patient's prognosis [11].

In this issue, Covinsky and colleagues [14] report the results of a prospective cohort study of 572 hospitalized medical patients older than 70 years of age. One third of the patients reported six or more symptoms of depression on a 15-item screening scale; in this group, the patients' overall condition was more likely to deteriorate and less likely to improve during hospitalization and after discharge. Strengths of this study include the use of several measures of dependency and health status; assessment of outcome at three points (hospital discharge and 30 days and 90 days after discharge); adjustment for important confounders, such as health status and severity of illness at hospital admission; and clearly discussed study limitations.

Covinsky and colleagues assessed symptoms of depression by using the Geriatric Depression Scale, a measure commonly used in research in medically ill elderly patients because of its focus on nonsomatic symptoms of depression. However, this instrument does not allow physicians to make criteria-based diagnoses of major depression (the mood disorder for which the efficacy of antidepressant agents has been best substantiated) and was not among the measures critically reviewed in a recent evaluation of case-finding instruments for depression [15]. Clinicians certainly need not feel compelled to incorporate geriatric-specific depression instruments into their practices. They can choose a brief, validated questionnaire [15] or directly ask their patients about the nine diagnostic symptoms (one mnemonic is SPACE DIGS: Sleep, Psychomotor retardation/agitation, Appetite, Concentration, Energy, Depressed mood, Interest, Guilt, Suicidal). In fact, a single question about depressed mood has a sensitivity for major depression of 85% to 90% [16, 17].

Randomized clinical trials of major depression have typically excluded acutely ill, hospitalized elderly patients. Although further evidence is needed to determine whether treatment will improve the types of geriatric impairment (such as dependency in activities of daily living) seen by Covinsky and colleagues, the known effect of major depression on health-related quality of life and even mortality justifies case finding and treatment.

Although it is likely that many of the patients in Covinsky and colleagues' study who had six or more symptoms of depression on the Geriatric Depression Scale had major depression, the authors did not confirm this by using structured interviews. Nonetheless, individual treatment decisions need not always hinge inflexibly on diagnostic criteria. Strictly defined, the diagnostic threshold for major depression requires the presence of at least five of nine criterion symptoms, but the degree of impairment and the duration of symptoms are also important. I would not withhold a trial of antidepressant medication from a patient who had four persistent and disabling symptoms (for example, depressed mood, insomnia, fatigue, and anhedonia), but I might choose watchful waiting for a person with six symptoms of recent onset that had been triggered by illness or stress and were associated with only mild impairment.

The hospital can be a particularly difficult setting in which to tackle depression: An acute medical illness usually takes precedence; hospital stays are shorter; care may be given by physicians other than the patient's primary care physician; and therapy with antidepressant medication, if initiated, may take 3 to 6 weeks to achieve benefits and necessitates close follow-up after hospital discharge. After conducting structured interviews among 128 patients admitted to a general medicine ward, Kathol and Wenzel [18] found that one third of patients had major depression. Sequential assessment during the hospital stay showed that symptoms of depression improved substantially in most patients, typically within the first 3 days. Although these patients were younger and had less functional impairment than those studied by Covinsky and colleagues, the results suggest that monitoring of symptoms of depression in acutely ill hospitalized patients is warranted and that antidepressant medication or other treatment should be reserved for patients who remain depressed.

Cost-containment efforts have increasingly shifted the management of depression to primary care. Although this is suitable in many cases, managed care systems must be flexible enough to accommodate more frequent and longer primary care visits in the early phases of treatment. The first 6 to 12 weeks of therapy are a particularly critical time during which to ask patients about side effects of and adherence to medication (one third of patients discontinue therapy with antidepressant medication during the early weeks of treatment), to assess treatment response, to educate the patient, and to encourage increasing activity.

Will care by mental health specialists be reserved for the few patients who are suicidal, are psychotic, are bipolar, or have not responded to treatment? "Either/or" may be the wrong model: One clinical trial [19] showed that collaboration between medical providers and mental health specialists was superior to the usual primary care treatment of depression. Authors of a recent cost-effectiveness analysis concluded that shifting patients away from mental health specialists may decrease costs but may worsen functional outcomes [20].

Asking all clinicians to better recognize major depression is reasonable. However, determining the types and amount of support that busy clinicians need to achieve an optimal outcome for the depressed patient is an essential task for health care organizations.