Why Am I Gaining Weight On Prozac?

QUESTION:

Dear Dr. Heller,

I have been taking Prozac for almost 4-5 years and during that time have gained about 50 lbs.  I had not tied one to the other until recently.  I regularly exercise and eat well sometimes, others not - not enough to gain 50lbs!

After searching the Web it seems that Prozac is being connected with weight gain quite a bit lately.  Even when you eat right and exercise people are having trouble getting rid of the weight.

What are your thoughts and suggestions for this? 

ANSWER:

It's not a phenomenon I have observed or encountered in the medical literature, although there are some people who would likely be at higher risk...

1) Those with the BPD and untreated GAD (generalized anxiety disorder).  These people would experience increased anxiety on Prozac, causing dysphoria (anxiety, rage, depression and despair) and increased food intake to "treat" the anxiety.

2) Prozac sometimes causes a lack of zest for life, and the addition of Wellbutrin can resolve this problem.  When tired and bored people commonly eat.