WASHINGTON — Use of antidepressant drugs in the United States doubled between 1996 and 2005, probably because of a mix of factors, researchers reported on Monday. About 6 percent of people were prescribed an antidepressant in 1996 — 13 million people. This rose to more than 10 percent or 27 million people by 2005, the researchers found. ‘Significant increases in antidepressant use were evident across all sociodemographic groups examined, except African Americans,’ Dr. Mark Olfson of Columbia University in New York and Steven Marcus of the University of Pennsylvania in Philadelphia wrote in the Archives of General Psychiatry. ‘Not only are more U.S. residents being treated with antidepressants, but also those who are being treated are receiving more antidepressant prescriptions,’ they added. More than 164 million prescriptions were written in 2008 for antidepressants, totaling $9.6 billion in U.S. sales, according to IMS Health. Drugs that affect the brain chemical serotonin like GlaxoSmithKline’s Paxil, known generically as paroxetine, and Eli Lilly and Co’s Prozac, known generically as fluoxetine, are the most commonly prescribed class of antidepressant. But the study found the effect in all classes of the drugs. Olfson and Marcus looked at […]