Antidepressants are medications used in the treatment of major depressive disorder, but have also found to be effective in the treatment of several other conditions, including ADHD, eating disorders, OCD, and even chronic pain. There are six major categories of antidepressants: selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), monoamine oxidase inhibitors (MAOIs), tetracyclic antidepressants (TeCAs) and noradrenic and specific serotonergic antidepressants (NaSSAs).
Before the 1950s, the most common treatment for depression involved opioids, amphetamines, or methamphetamine. In 1951, however, two Staten Island physicians began clinical trials on two medicines designed to treat tuberculosis, which resulted in renewed vigor among hopeless patients. Reading the results, a Cincinnati psychiatrist used one of those medicines, isoniazid, on his patients, calling the medication an antidepressant.
In 2013, antidepressants were the most common prescribed medication in the United States. As many as 16 million Americans are considered to be long-term users, with about 70 percent of that number being women. The most commonly prescribed antidepressants in America today are Zoloft, Celexa, Prozac, and Lexapro, all of which are SSRI antidepressants. Results are mixed as to the efficacy of antidepressants when treating mild depression.