The reason has to do with the way drugs are tested and approved. To get F.D.A. approval, a drug has to beat a placebo in two randomized clinical trials that typically involve a few hundred subjects who are treated for relatively short periods, usually 4 to 12 weeks.So drugs are approved based on short-term studies for what turns out to be long-term — often lifelong — use in the world of clinical practice.

What do I say to a depressed patient who is doing well after five years on such a drug but can’t stop without a depressive relapse and who wants reassurance that the drug has no long-term adverse effects?I usually say that we have no evidence that the drug poses a risk with long-term use; and since the risk of untreated depression is much greater than the hypothetical risk of the drug, it makes sense to stay on it.

The drugs save lives, and we often have no choice but to use them — even if we have questions about their long-term use. But the questions are big ones, and we owe it to our patients to try to answer them.
(Richard A. Friedman is a professor of psychiatry at Weill Cornell Medical College).

Very interesting clip. i know two people who are lon term Prozac users. It seems it's impossible to get off this medication.

The drugs save lives, and we often have no choice but to use them

Indeed. Sometimes it comes down to a simple choice - a pill or a bullet.