Selective Serotonin Reuptake Inhibitors (SSRIs)

"I realized after taking Prozac that I'd been depressed all my life. I could never really answer the question 'Why do people live? What's the point?' When I was depressed, I couldn't function. A big day was getting the newspaper out of the driveway. Now I'm totally optimistic about everything."

—Joan, 42, business owner

It looks ordinary enough, this little green-and-white capsule called Prozac. Not even its manufacturer, Eli Lilly, claims to know exactly why its product works. But more than 10 million people have taken this drug for depression, and more than 70 percent of them have gotten better. Prozac today is the most popular antidepressant ever.

"I used to walk around with a black cloud over my head," explains Marie, 41. "I was chronically depressed. That's how I felt about life; it was an abyss. But after taking Prozac, my depression is simply gone. I'm not a different person, but I'm a better person."

If you've had a depressive episode recently, odds are that the first drug your doctor tries will be one of the SSRIs: Prozac (fluoxetine), Celexa (citalopram), Luvox (fluvoxamine), Zoloft (sertraline), or Paxil (paroxetine).

These drugs have moved to the forefront of modern psychiatric treatment because they work as well as any of the older antidepressants while causing far less serious side effects. Many SSRIs also treat a wide range of other disorders in addition to depression, including obsessive-compulsive disorder (OCD), social phobia, anxiety or panic disorders, post-traumatic stress disorder, eating disorders, premenstrual syndrome (PMS), or menopause-related symptoms.

How SSRIs Work

Remember that the physiological cause of depression lies in the nerve cells in the brain. When the levels of the brain messengers called neurotransmitters are too low, messages can't cross the gaps between brain cells, and communication in the brain slows down. While there are about 100 different kinds of neurotransmitters, the most important ones that seem to be related to depression are serotonin, norepinephrine, and dopamine. When levels of these chemicals are too low, you get depressed. Drugs that boost these chemical levels can relieve depression.

SSRIs target the neurochemical serotonin. When serotonin is released in the brain, it is reabsorbed by the brain cells to be used at another time for another message. This process of reabsorbing is called reuptake . If you're depressed, you don't have enough serotonin and other neurotransmitters, so by interfering with the reuptake of these chemicals, more is available to help send messages and boost communication. A drug that can interfere (inhibit) the reabsorption (reuptake) of serotonin alone is "selective"—hence, the selective serotonin reuptake inhibitors.