Sertraline is used to treat depression, panic attacks, obsessive compulsive disorder, post-traumatic stress disorder, social anxiety disorder (social phobia), and a severe form of premenstrual syndrome (premenstrual dysphoric disorder). This medication may improve your mood, sleep, appetite, and energy level and may help restore your interest in daily living. It may decrease fear, anxiety, unwanted thoughts, and the number of panic attacks. It may also reduce the urge to perform repeated tasks (compulsions such as hand-washing, counting, and checking) that interfere with daily living. Sertraline is known as a selective serotonin reuptake inhibitor (SSRI). It works by helping to restore the balance of a certain natural substance (serotonin) in the brain.