One in 10 Americans is on antidepressants, according to a new survey by the Centers for Disease Control -- a 400 percent increase from a decade ago, leading to questions about whether the drugs are overprescribed.

According to the 12,000-person survey, antidepressants are the third most common type of drug prescribed in the U.S., and the most common among Americans aged 18 to 44. Antidepressant use is most prevalent among women aged 40 to 59, of whom 23 percent reported taking the drugs.

But despite how common antidepressant use was among the general population, only a third of people with severe depression took antidepressants. That included 40 percent of women with severe depression and 20 percent of men with severe depression.

Perhaps the most striking finding, though, was that most people who take antidepressants don't see mental health professionals. In fact, less than a third of people taking one antidepressant and less than half of people taking more than one antidepressant reported seeing a mental health professional in the past year.

Primary Care Physician Involvement

Increasingly, Americans are receiving antidepressant prescriptions from their primary care doctors without ever seeing a psychiatrist. This trend is largely due to the fact that not everyone with depression realizes they have it. They may come to their primary care doctor with other symptoms, like headaches, insomnia or loss of appetite, that can be indicative of depression, and doctors are now better trained to recognize those warning signs.

It's a required part of training in our specialty, Lee Green, a professor of family medicine at the University of Michigan, told ABC News. We refer patients with the most complex or treatment-resistant depression to psychiatrists for medication management, but that is only a minority of people with depression. Most patients can and should get their antidepressant prescription from their family doctor.

Psychiatrists realize that most depressed patients will go to their primary care doctor first, and so many of them are making a concerted effort to train primary care doctors in the basics of recognizing and treating depression.

The reality is that there are not enough mental health care providers around to treat all who need it, Gary Small, a psychiatrist and director of the UCLA Center on Aging, told ABC News. Part of what we do as psychiatrists is teach doctors how to diagnose and treat depression so that a lot of depression can be handled in primary care.