Zoloft, also known as sertraline, is an antidepressant medication that works by increasing the levels of serotonin, a natural substance in the brain that helps maintain mental balance. It is used to treat a variety of mental health conditions, including depression, panic attacks, obsessive-compulsive disorder (OCD), post-traumatic stress disorder (PTSD), social anxiety disorder, and premenstrual dysphoric disorder). Zoloft may improve mood, sleep, appetite, and energy levels, and may help restore interest in daily living. It may also decrease fear, anxiety, unwanted thoughts, and the number of panic attacks, and reduce the urge to perform repeated tasks that interfere with daily living. Zoloft is known as a selective serotonin reuptake inhibitor (SSRI), which works by helping to restore the balance of serotonin in the brain.