By Will Boggs MD

NEW YORK (Reuters Health) - Most adults in the U.S. who screen positive for depression are not being treated for depression, according to results from Medical Expenditure Panel Surveys (MEPS).

"With the recent increase in prescribing of antidepressant medications, many physicians might assume that undertreatment of depression is no longer a widespread problem," Dr. Mark Olfson from College of Physicians and Surgeons, Columbia University and the New York State Psychiatric Institute in New York City told Reuters Health by email. "This study makes clear, however, that most American adults who screen positive for depression receive no treatment for their symptoms."

Surveys from the early 2000s show that about half of U.S. adults with a lifetime medical history of major depressive disorder had never received treatment for depression. Still, little is known about the extent to which adults with depression in the U.S. receive depression care and the extent to which such patients are matched based on their illness severity to appropriate treatments and healthcare professionals.

Dr. Olfson and colleagues used data from the 2012 and 2013 MEPS to examine the prevalence and treatment of adults with screen-positive depression (a Patient Health Questionnaire-2 score of 3 or less). They also assessed whether serious psychological distress was associated with more intensive treatment.

About 1 in 12 adults (8.4%) screened positive for depression, but the prevalence varied widely from 18% among adults in the lowest income group to 3.7% in the highest income group.

Only 28.7% of those who screened positive for depression received any depression treatment during the survey year, although 78.5% of those with screen-positive depression who received no depression treatment made at least one medical visit during that time, according to the August 29th JAMA Internal Medicine online report.

"Some groups, such as men and adults with less education, as well as ethnic and racial minorities, were especially unlikely to receive any treatment for their depressive symptoms," Dr. Olfson said.

Overall, 8.1% of adults received treatment for depression, but only a minority of those had screen-positive depression (29.9%) or serious psychological distress (21.8%).

The most common treatments for depression were antidepressants (87.0%), followed by psychotherapy (23.2%), anxiolytics (13.5%), antipsychotics (7.0%), and mood stabilizers (5.1%).

Patients with more serious distress were less likely than less distressed patients to be treated with antidepressants but more likely to be treated with antipsychotics, anxiolytics, mood stabilizers, psychotherapy, or the combination of antidepressants and psychotherapy.

Nearly three-quarters of patients who were treated for depression were treated exclusively by general medical professionals, and those patients were less likely than patients treated by psychiatrists or other mental health professionals to have screened positive for depression or serious psychological distress.

About half of college graduates with serious distress were treated by psychiatrists, compared with less than a third of their counterparts with less education.

"The results highlight ongoing challenges in aligning depression care with patient needs," Dr. Olfson said. "Expanding the use of simple depression screening tools in primary care is a good first step to increase identification of depression and to guide matching patients to appropriate depression treatment. Beyond screening, integrating mental health services into primary care, though far more complicated, has been shown to improve key patient outcomes of outpatients with depression."

"Although most physicians are far more comfortable treating uncomplicated depression than they were years ago, many depressed patients continue to receive no treatment for their symptoms," he concluded. "Because untreated depression is highly distressing, impairs social function, reduces work productivity, and increases the risk of suicide, ischemic heart disease, and nonadherence to medical treatments, it is critically important for physicians to remain ever watchful for undetected depression."

Dr. Dara H. Sorkin from the University of California, Irvine, who has published extensively on depression and its treatment, told Reuters Health by email, "Certainly, screening patients as they present for general medical care will increase the detection of depression, but detection is not enough. The health care system needs to be better prepared to offer patients appropriate mental health services that are affordable, concordant with their personal and cultural values and linguistic preferences, and in line with what has been shown to be most effective given an individual's mental health need."

"Critical gaps in mental health care continue to persist, particularly for individuals from diverse racial/ethnic backgrounds, low income individuals, less educated adults, and those who lack insurance," she said. "Although recent changes in healthcare associated with the Affordable Care Act may remedy some of these disparities, they are not likely to completely eradicate the many barriers that patients face when seeking and receiving mental health treatment."