Screening for Depression in Clinical Practice: An Evidence-Based Guide

Depressive disorders are highly prevalent, but our health care system misses the diagnosis of depression in approximately half of affected patients. Missed diagnoses affect medical outcomes, economic productivity, and quality of life for these patients. Because initial detection of depressive disorder usually falls to the primary care provider-whose contact with patients is brief and must cover a wide range of health matters-it is of great public health importance that reliable and acceptable screening methods are available to identify depression.

Screening for Depression in Clinical Practice, which reviews the current body of knowledge on mental health screening in the medical setting, is a reference text written primarily for the consultation-liaison specialist, but it will be of use to the general psychiatrist and the interested primary care physician or medical specialist.

The book begins with the chapter, “Is the Syndrome of Depression a Valid Concept?” This is an interesting and important philosophic question, but it belongs in another book entirely and readers seeking evidence-based insight into depression screening may be turned away by it. However, for the persistent reader, the book moves to matters relevant to its title, with chapters that address in great depth:

• Scales and tools for screening, and their characteristics

• Why so many cases of depression are missed

• How available scales could be improved

• Measurement of the effectiveness of screening

• Determining which primary care clinicians benefit from using depression screening tools

• How to improve outcomes when possible depression is identified

• Potential roles for (computer) technology in screening

• Optimizing the efficiency of depression screening in primary care

• Evidence for (and against) use of specific (ie, nonsomatic) scales for depression in medical settings

• Depression screening in patients with neurological disorders, cancer, cardiovascular disease, and diabetes

Despite the wealth of supportive data presented in this substantial text, the editors surprisingly conclude the evidence indicates that routine screening for depression in primary care is without measurable benefit to patient outcome. In the concluding essay, “Commentary and Integration,” coeditor James Coyne argues that in specialty care settings (eg, oncology, neurology, cardiology, diabetology, perinatology, and so on), initiation of effective depression treatment in newly identified cases is unlikely and the screening effort may detract from attention to identified medical problems.

Furthermore, despite widespread enthusiasm for more screening, Dr Coyne warns that there may be more harm than benefit in increased screening in the primary care setting. By exerting efforts to identify new cases of depression through routine screening, limited resources will be diverted from the care of already identified patients with depression, who, he argues, require better treatment than they are currently getting. He refers to mathematical models that show greater cost-effectiveness in improving the care of identified depressed patients than in “introducing more patients into . . . inadequate treatment.”

These are curious words, appearing as they do at the end of an extensive multi-author review of the substantial and largely supportive body of literature on depression screening. The conclusion offered-that we should dismiss the project of depression screening because of perceived inadequacy of depression treatment in primary care-seems a non sequitur. Nevertheless, these aims are not mutually exclusive. It would serve the best interests of patients both to make every reasonable effort to detect cases of depressive illness and to optimize the quality of treatment that is provided to identified cases.