Most Americans who screen positive for depression don’t receive treatment, while most who do receive treatment don’t actually have the condition. These are among the findings of a new study published in JAMA Internal Medicine.

“Over the last several years, there has been an increase in prescription of antidepressants,” said Mark Olfson, a professor of psychiatry at the Columbia University Medical Center and lead author of the study. “In that context, many people assumed that undertreatment of depression is no longer a common problem.”

But Olfson found the opposite to be true after analyzing data from surveys that included questionnaires to screen for depression. Of the 46,417 adults surveyed, 8 percent answered in ways that suggested they had depression, but only 29 percent of those who seemed to need help received any treatment for it.

“The findings highlight that there are continuing challenges in aligning depression care with patient needs,” he said.

Adults in the lowest income group were five times as likely to have signs of depression as were those in the highest income group. But they were also less likely to receive treatment.

Among the people who received treatment for depression, only 30 percent had screened positive for depression. And those with less serious depression were more likely to receive antidepressants. That’s a problem of overprescription, Olfson said, because studies have shown that antidepressants are no more effective for mild depression than a placebo.

“Being a little less aggressive in medication in mild depression would be beneficial,” he said. “There are simpler forms of psychological interventions that can be adapted for primary care.” For example, patients can get counseling, exercise or practice yoga.

The researchers concluded that those with serious psychological distress were more likely to be treated by psychiatrists than by general medical professionals, although this trend was not seen in older patients, African-Americans, the uninsured or those with less education.

“Some when they have depression don’t believe they require treatment or that they could benefit from treatment,” Olfson said. “People are visiting doctors, but the attention is to current, pressing medical problems.”

Olfson found that most people with untreated depression make at least one visit annually to a primary care doctor. If depression screening and mental health services were integrated into primary care, he said, there would be better access to assistance and awareness about the illness.

“If you give them a referral to a mental health clinic, they simply won’t go if they don’t think they have a mental health disorder,” he said. “By embedding the services within primary care, it becomes more accessible and less stigmatized.”

Olfson said many primary care doctors expressed frustrations in finding mental health professionals, particularly in small towns and rural areas, so prescribing antidepressants might become their only option. If there were a mental health professional right in the clinic, patients might get services that a primary care doctor cannot offer, such as counseling and psychotherapy.

“Depression really is a serious condition, and we’re finding that so many Americans aren’t receiving care,” he said. “I hope that [this study] brings attention to this situation.”