I've been on a massive number of psych meds and as far as I can tell, there hasn't been a single one that did not cause me to gain at least some weight. I started out underweight...low-weight kid/teen, and when I was 25, even after a pregnancy I weighed 102 and was always trying to gain weight. When I was pregnant with my second child the MD put me in the hospital 'cause I was so thin, and losing weight due to morning sickness.

Then I went on psych meds and gained weight. Some weight, maybe 40 lbs., so I was pretty 'normal' still.

When I was 49 (3 years ago) I went on Seroquel and gained 100 lbs within a year. I am finally going off Seroquel, on Geodon instead, and hoping I lose some of the weight. By the way, my eating has always been decently healthy - never binged, for example, or eaten lots of junk food. Ever. The meds just plain cause weight gain.