Will the anti depressant venlafaxine make me gain weight or have trouble losing weight?

Effexor (venlafaxine): I have seen both, depending on your body chemistry & the dose.

One study that was: Short term (6 wks) reported an average weight loss of 2 to 3 lbs in patients treated with venlafaxine. However, pre-marketing trials showed weight gain. Military personnel i treated with venlafaxine often had to stop the medication due to the combination of increased weight & increased blood pressure. In the military you can lose your career if you don't stay within weight limits.