Can antidepressants and anti anxiety meds cause extreme fatigue and weight gain?

Yes: Some of these medications are more prone to these side effects than others. Consult with your physician to select medications that minimize this risk.

It *may*, depending: Medications used to treat anxiety and depression (some of the same medications treat both at the same time, others do not) have been known to cause weight gain in some patients and weight loss in others - and excessive sleep in some people and insomnia in others. It depends on the specific medication and each person’s unique chemistry, and there is no predicting how it will affect each person.