The U.S. Preventive Services Task Force (USPSTF) now recommends screening all adults for depression in practices that have a system in place to assure accurate diagnosis, effective treatment, and follow-up.¹ The USPSTF rates this recommendation as a “B” intervention: physicians should routinely provide the service to eligible patients; there is at least fair evidence that the intervention improves important health outcomes and that the benefits outweigh the potential harms.

Because the morbidity, mortality, and cost of not recognizing and treating depressive disorders are so high, and the probability of missed diagnosis is significant, there has been keen interest in screening tools to aid in identifying depressive disorders.^2–4

Depression screening measures have been developed for patients of various ages and conditions. In this issue of American Family Physician, Sharp and Lipsky² present a comparative review of some of the instruments that are of practical use in a primary care setting.

Since family physicians treat the majority of patients who are given therapy for a depressive disorder, they can readily recognize the patient who presents with major depression, and they often recognize many more subtle presentations. So why is a screening tool needed? Because a large group of patients will not present with depression in a straightforward manner, and the diagnosis often will be missed. For example, patients who present with multiple medical complaints have a proportionately increased probability of having an anxiety or mood disorder.⁵

Failure to recognize and treat a depressive disorder leaves the patient to suffer and to become a costly user of health care services, and it significantly increases the risk of mortality. Patients who have a myocardial infarction and have untreated depression may be at three times the risk of death by six months postinfarction than patients who were not depressed.⁶ Arrhythmic mechanism might be the link between depression and sudden cardiac death.⁷

Patients with Parkinson's disease, dementia, or Alzheimer's disease often have an existing depressive disorder or develop depression during the course of the disease. Treatment of the depressive disorder may enable the patient to achieve better functioning in activities of daily living, possibly to a degree that placement in a nursing facility may be delayed or avoided. However, depression often exists in the caregivers of such patients, and placement in a nursing facility often depends on the patient's caregiver and whether or not he or she has the mental and physical ability to continue to care for the patient.⁸ Thus, it is equally important to screen caregivers for depressive disorders, not only for the health of the patient, but also for the health of the caregiver.⁹

A study of high users of health care services revealed that 40 percent had an existing depressive disorder, and two-thirds had a lifetime history of depression.¹⁰ After adjusting for medical morbidity, health care costs for primary care patients with a depressive or anxiety disorder are typically 175 percent higher than costs for those with no anxiety or depressive disorder. The cost differences reflect higher use of general medical services rather than higher use of mental health care.¹¹

Although the USPSTF found insufficient evidence to recommend for or against routine screening in children and adolescents, it may make sense to screen many, if not most, adolescents. Depression in adolescents is associated with substance abuse, suicidal behavior, and acts of violence.

Most of the teenagers who shot and wounded or killed their peers at schools were reported to have shown signs and symptoms of depression before their violent outbursts. To be sure, the prevention of violence among adolescents is more complicated than simply screening for depressive disorders, but screening could be a start to identifying adolescents at risk for such dangerous behavior, initiating treatment, and monitoring their response.

Given the tremendous potential for primary care physicians to reduce morbidity and mortality, increase quality of life, reduce health care costs, and perhaps even prevent youth violence, primary care physicians should do as much as they can to improve the odds of finding hidden, subtle presentations of depressive disorders in patients of all ages. Screening tools help us to do this, and we cannot afford not to use them.

Physicians often wonder when to screen for depression. One approach might be to combine a screening tool with a health history questionnaire to be completed by the patient at the time of registration, and again at health maintenance visits or when it appears that depressive symptoms are present.

Investigating several screening instruments, determining which instruments best suit the particular needs of a primary care practice, becoming familiar and comfortable with the instruments, and using the instruments consistently are the most important steps in identifying patients who may benefit from treatment for depression. Recalling the definition of the USPSTF's “B” intervention, I believe the benefits of screening for depression outweigh the harms.

Depression screening instruments require a relatively small investment in time and money, yet the potential return on the investment is significant.