WEDNESDAY, Oct. 19 (HealthDay News) -- The rate of antidepressant use among Americans of all ages increased nearly 400 percent over the last two decades, and 11 percent of Americans aged 12 and older now take antidepressant drugs, according to a federal government report released Wednesday.

The analysis of 2005-2008 data from the U.S. National Health and Nutrition Examination Surveys also showed that antidepressants are the third most common prescription drug taken by Americans of all ages and the most frequently used by those aged 18 to 44.

Of people with severe depression, about one-third takes antidepressant medication. More than 60 percent of Americans taking an antidepressant drug have taken it for two years or longer and nearly 14 percent have taken the medication for 10 years or more, according to the U.S. Centers for Disease Control and Prevention researchers.

The investigators also found that less than one-third of people taking one antidepressant and less than half of those taking multiple antidepressants had seen a mental health professional in the past year.

Commenting on the report, Dr. Tolu Olupona, an assistant clinical professor of pediatrics and psychiatry at Mount Sinai Hospital Adolescent Health Center in New York City, said that "it is surprising to learn that only about one-third of those taking one antidepressant have seen a mental health professional within the past year. The number of those who have seen a mental health professional do appear to improve for those taking two or more antidepressants."

But, Olupona pointed out, "the data does not show if those who were not being monitored by a mental health professional were being monitored by primary care physicians. Nevertheless, the rate of follow-up by a mental health professional needs to be improved."

In addition to these findings, the researchers reported that women are 2.5 times more likely to take antidepressants than men and 23 percent of women aged 40 to 59 take antidepressants, more than in any other age/sex group.

Forty percent of women and 20 percent of men with severe depression take antidepressants, as well as more than one-third of women and less than one-fifth of men with moderate depression, the results showed.

Among all adults, those aged 40 and older and more likely to take antidepressants than younger people. There were no significant differences between women and men in the length of use of antidepressants.

Fourteen percent of white people take antidepressants, compared with 4 percent of blacks and 3 percent of Mexican Americans. The researchers found no association between income and antidepressant use.

About 8 percent of Americans aged 12 and older without current depressive symptoms took antidepressants. This may include those taking the drugs for reasons other than depression and those taking the drugs for depression who are being treated successfully and do not currently have depressive symptoms, Laura Pratt and colleagues at the CDC's National Center for Health Statistics explained in the October NCHS Data Brief.

According to Olupona, "these medications can be effective for treatment of depression, anxiety disorders and some other disorders," but it is best when the patients receive "careful follow-up to manage efficacy, drug-drug interactions, side effects, medication compliance and a host of other medication management issues."

More information

The American Academy of Family Physicians has more about antidepressants.