Aug. 3, 2009 -- Antidepressant use has nearly doubled in the U.S, according to a new study.
Meanwhile, the use of psychotherapy by those prescribed the antidepressants has declined during the same period studied, from 1996 to 2005.
"I expected there to be an increase [in antidepressant use], but I didn't expect the increase to be as large as we actually found," says Mark Olfson, MD, MPH, professor of clinical psychiatry at New York State Psychiatric Institute of Columbia University, who co-authored the study with Steven C. Marcus, PhD, of the University of Pennsylvania, Philadelphia.
''Ten percent of the population is being treated with an antidepressant during the course of a year," he says. That compares to 5.8% in 1996, he found.
Although part of the uptick can be linked to the fact that mental health treatment is becoming more common and accepted, Olfson tells WebMD that he fears the medications may sometimes be prescribed "in a casual way."
The study appears in the Archives of General Psychiatry.
Olfson and Marcus analyzed data from the Medical Expenditure Panel Surveys, sponsored by the Agency for Healthcare Research and Quality, which provides national estimates in the U.S. about health care use and costs.
For the 1996 survey, nearly 19,000 people aged 6 and older were included, and more than 28,000 in the 2005 survey. A designated adult in each household answered questions about prescribed medications, medical visits, and other information.
The rate of antidepressant treatment increased from 5.84% to 10.12 % -- or from 13 million people to about 27 million, the researchers found.
One exception to the trend involved African-Americans. "African-Americans really did stand out as one group that didn't experience a significant increase in antidepressant use," Olfson says. In 1996, 3.6% of African-Americans surveyed were on antidepressants and 4.5% in 2005.
Another important finding, Olfson says, is that fewer people on antidepressants surveyed in 2005 also took part in psychotherapy or "talk therapy." Although 31.5% of those surveyed in 1996 on antidepressants also did talk therapy, just 19.8% of those surveyed in 2005 both took antidepressants and participated in psychotherapy.
Often, the two are recommended together for depression.
Antidepressant Use Trends: Study Interpretations
The researchers say a number of factors explain the increasing use of antidepressants. "There has been broad and growing acceptance of antidepressant medicine in the U.S.," Olfson tells WebMD.
In an unrelated survey released last week, researchers found that American attitudes toward psychiatric medicines are becoming more positive. The researchers compared the responses of people in surveys done in 1998 and 2006.
Other factors explaining the increase, according to Olfson:
Major depression is more common. Two surveys found the prevalence of major depression in adults rose from 3.3% in 1991-1992 to 7.1% in 2001-2002.
Since 1996, several new antidepressants have come on the market.
Clinical guidelines support the use of antidepressants for conditions other than depression, such as anxiety disorders.
The lower increase in antidepressant use among African-Americans may be cultural, Olfson says, with a tendency to embrace psychotherapy over medication. "There is also some evidence that African-Americans as compared to whites have lower rates of depression," he says. That may be part of the story as well."