Zoloft is an antidepressant in a group of drugs called selective serotonin reuptake inhibitors (SSRIs). Sertraline affects chemicals in the brain that may become unbalanced and cause depression, panic, anxiety, or obsessive-compulsive symptoms. Zoloft is used to treat depression, obsessive-compulsive disorder, panic disorder, anxiety disorders, post-traumatic stress disorder (PTSD), and premenstrual dysphoric disorder (PMDD). Zoloft patient assistance programs are designed to help patients receive prescribed medication for free or for a significantly reduced cost. See PharmacyDrugGuide for more information.