That’s how the class came to be known as “selective serotonin reuptake inhibitors” — they prevent (inhibit) serotonin (and only serotonin) from experiencing too much or too long of a reuptake process. This makes more serotonin available in the brain. According to Sheldon H. Preskorn, M.D., professor and chair of the department of medicine and behavioral sciences at University of Kansas School of Medicine, Wichita, and author of Applied Clinical Psychopharmacology, SSRIs are effective for a significant number of individuals who use them as directed for this purpose.

The SSRIs’ Pedigree

SSRIs weren’t the first prescription antidepressants. That distinction goes to iproniazid, a member of the antidepressant class known as monoamine oxidase inhibitors (MAOIs).

Iproniazid was discovered accidentally in the early 1950s when the tuberculosis patients for whom it was prescribed experienced not only improvements in their tuberculosis, but also in their mood and activity levels. Later in the decade, the first antidepressant in the tricyclic class, Imipramine (Tofranil), was found to have good results for depression, although it had been originally developed as a treatment for schizophrenia.

It took almost 30 years for researchers to unravel enough of the brain’s functioning to understand that MAOIs and tricyclics probably work by promoting increases in the levels of certain brain chemicals, such as serotonin and norepinephrine. Then the search was on for medications that could do this selectively, that is, increase one of the chemicals responsible for improved mood, but not all of them at the same time.

The first SSRI to be approved by the U.S. Food and Drug Administration was Prozac in 1987; the most recent was Celexa in 1998. The five SSRIs presently approved for use in the United States are:

  • fluvoxamine maleate (Luvox) manufactured by Solvay
  • paroxetine (Paxil) manufactured by Smith Kline Beecham
  • sertraline (Zoloft) manufactured by Pfizer
  • citalopram (Celexa) manufactured by Forest Laboratories
  • fluoxetine (Prozac) manufactured by Eli Lilly