Ok since i been put on remeron (mirtazapine) i gained 70 pounds ! will this drug cause this massive weight gain?

Remeron (mirtazapine) weight gain: Remeron (mirtazapine) can certainly increase appetite and cause weight gain, especially if you aren't mindful of what you're eating. I hope the medication is providing desired effects as far as anxiety and depression -- but you do need to attend to exercise and healthy food.

It Can: Mirtazapine (Remeron) is an antidepressant that often has the side effect of increasing appetite thus causing weight gain.