Selective serotonin reuptake inhibitors (SSRIs) are a class of antidepressant medications prescribed for the treatment of certain mental disorders. They are most often used for depression, but may also help manage symptoms of anxiety disorders, including obsessive-compulsive disorder, post-traumatic stress disorder, or social anxiety disorder. In some instances, they have also been used to treat impulse-related disorders like anorexia or trichotillomania (hair-pulling disorder)—though evidence of their efficacy for these disorders is mixed, and they are not a first-line treatment in many cases.
Though their exact mechanism of action remains unknown, it is believed that SSRIs work by increasing the amount of the neurotransmitter serotonin in the brain; serotonin is thought to be low in individuals with major depression and anxiety disorders. The first major SSRI to be introduced to the general public was fluoxetine (more commonly known as Prozac) in the late '80s; Prozac remains one of the most popular SSRIs today.
Though the class of drugs was developed in the hopes of eliminating some of the unpleasant (and dangerous) side effects of their predecessors, certain side effects remain. Some, like an increased risk of suicidal ideation or cardiac arrest, are very serious, while others, like dry mouth or sexual dysfunction, can be troublesome but are not life-threatening. Because of their side effects, however—as well as their inconsistent results in treating depression—they continue to generate controversy. Like most antidepressants, SSRIs appear to be most effective when used in combination with cognitive behavioral therapy or other forms of therapy.