Eleven percent of Americans ages 12 years and older took antidepressants during the 2005-08 study period, the authors write. They add that though the majority of antidepressants were taken to treat depression, the drugs also can be used for anxiety disorders and other conditions.

The data are from the National Health and Nutrition Examination Surveys, which included information from 12,637 participants about prescription-drug use, antidepressant use, length of use, severity of depressive symptoms and contact with a health professional.

Mental-health professionals not associated with the survey cited several reasons as possible explanations for the spike:

•The struggling economy and the record number of layoffs and home foreclosures. "These drugs can be very helpful for people who need them,'' says Elaine Ducharme, a psychologist and public educator in Connecticut for the American Psychological Association. "People should expect to be depressed after a layoff. They should not be put on a drug, though, unless they have an acute problem."

•Ad campaigns waged by pharmaceutical companies citing benefits of the drugs.

•Families who might be reimbursed by health insurance companies for a prescription but may delay getting therapy from a mental-health professional because of the cost of treatment.

In fact, less than one-third of Americans taking one antidepressant and less than one-half of those taking multiple antidepressants have seen a mental-health professional in the past year, the report shows.

"Unfortunately, some families are looking for a quick fix, but a pill is never going to get to the root of the problem," says David Palmiter, a psychologist and author of Working Parents, Thriving Families: 10 Strategies That Make a Difference.

Ducharme agrees. "That is the thing that bothers me the most," she says. "These drugs can be dangerous, and there needs to be follow-up care."

The survey also found that nearly one in four women ages 40 to 59 are taking antidepressants. Women are more likely to take antidepressants; however, among those taking antidepressants, men were more likely than women to have seen a mental-health professional in the past year.

The survey found that about one in 25 teens take the medication.