Which antidepressant is known to cause weight gain and may be chosen when weight gain is desired?

• A. Mirtazapine
• B. Sertraline
• C. Fluoxetine
• D. Venlafaxine

Answer: (A)

Weight gain is a known and relatively common effect of mirtazapine. This antidepressant works as a noradrenergic and specific serotonergic antidepressant with strong histamine H1 antagonism. The H1 blockade and increased appetite from its pharmacologic actions often lead to weight gain and improved appetite, which can be desirable in patients who are underweight or have depression-associated anorexia or poor intake. In contrast, other common antidepressants like fluoxetine are more often associated with weight loss, while sertraline and venlafaxine tend to be weight neutral or cause only modest changes. For these reasons, mirtazapine is the best choice when weight gain is the goal.