Selective Serotonin Reuptake Inhibitors (SSRIs) have been used in the treatment of depression since the late 1980s. Serotonin–norepinephrine reuptake inhibitors (SNRIs) were introduced in the 1990s. It is proposed that SSRIs work by increasing serotonin activity in the brain, and that SNRIs work by increasing both serotonin and norepinephrine. These are chemicals that have been linked to the regulation of mood.
Although these drugs were initially indicated for depression, they have also been FDA approved for other conditions, including anxiety disorders, posttraumatic stress disorder, premenstrual dysphoric disorder and fibromyalgia. Antidepressant medication (ADM) use has dramatically increased over the last few years in the United States; about 1 in 10 Americans aged 12 and over take an ADM. This document reviews drugs classified as SSRIs or SNRIs, although a bulk of the research focuses on SSRIs.