*****FROM ABC NEWS MEDICAL UNIT*****
Hi marymak49 and thank you for your question. Here is an answer from Dost Ongur, M.D., Clinical Director, Schizophrenia and Bipolar Disorder Program, McLean Hospital:
There is a well-known phenomenon of the newer antidepressant medications (such as Prozac) "wearing out" in some people for whom they used to work very well. We don’t know why this happens, or to whom it will happen, but it probably has to do with long-term adaptations in the brain which reduce the effects of the medication. The good news is that if you are losing the effect of the medication and feel it is time to try something new, many of the other antidepressants seem to work fine in this situation. The choice of what to try next depends on the person’s specific history, side effect profile etc. so you need to talk to a professional to decide how to proceed.