answer:I suppose it depends on the anti-depressant. I know that Zyprexa and Seroquel, similar type drugs, can cause large weight gains with Zyprexa being up to a 40% weight gain, according to my own physician. They are both also associated with the onset of diabetes. My guess is that the chemical action of the anti-depressants on brain chemistry causes the weight gain. I don’t think it is due specifically to uncontrolled over-eating.