Sertraline (trade names Zoloft, Lustral) is an antidepressant. It was introduced by Pfizer in 1991. Sertraline is mainly prescribed for major depressive disorder in adult outpatients. It is also prescribed for obsessive–compulsive, panic, and social anxiety disorders in both adults and children. In 2011, it was the third-most prescribed antidepressant on the U.S. retail market, with 37 million prescriptions.