Tough one. Many people struggle with this, but is is important to do so because weight gain is associated with all kinds of unpleasant things, like diabetes, heart disease, certain kinds of cancer.

I gained 70 lb on risperidol in about 7 months, and came down some when I came off it (gradually).

After a year away from atypical antipsychotics (tried Zyprexa very briefly, bad experience there) I recently started Seroquel and have noticed enhanced appetite and craving for sweets and cold stuff.

I drink a lot of water, stay away from the cookie aisle, ice cream section and snacks aisle. I try to eat low calorie, low fat food with a low glycemic index. If you google "glycemic index" you will find scads of info. Eating fiber also helps to keep the appetite under control. Google "high fiber foods" and you will come up with a list of those.

Above all, try to exercise daily. 30 minutes of some kind of aerobic thing, even brisk walking, will enhance your basal metabolism so that you burn more calories and turn fewer into fat. This can be hard to do when you are depressed, unfortunately