The SSRI's are notorious for causing weight gain and sexual side effects and the two most common reasons why people taking these meds with success for depression or OCD, stop taking them. Not everyone gains weight, but the best thing to do when starting the med. is monitor your weight closely and if you start to gain say 5 lbs in the first week, you could call your doctor and try another one. Don't wait until you have gained 30 lbs. It doesn't come off just because you stop it, you have to diet and exercise it off. You should work closely with your psychiatrist when starting any new med and monitor side effects closely. Not all side effects last, some subside after a few weeks on the med.
I was on two SSRI's for 5 yrs. and one was
Paxil, the one that is most likely to cause the most weight gain. I lost 40lbs. Go Figure!