Antidepressants and weight gain: What causes it?

Weight gain is a possible side effect of nearly all antidepressants. However, each person responds to an antidepressant differently. Some people gain weight when taking a certain antidepressant while others don't.

Generally speaking, some antidepressants seem more likely to cause weight gain than do others. These include:

• Tricyclic antidepressants such as amitriptyline, imipramine (Tofranil), and doxepin (Sinequan)
• Monoamine oxidase inhibitors (MAOIs) such as tranylcypromine (Parnate), isocarboxazid (Marplan) and phenelzine (Nardil)
• Paroxetine (Paxil)
• Mirtazapine (Remeron)
• Trazodone

Some antidepressants that may be less likely to cause weight gain include:

• Venlafaxine (Effexor)
• Bupropion (Wellbutrin)
• Selective serotonin reuptake inhibitors (SSRIs) other than paroxetine (Paxil) — fluoxetine (Prozac), sertraline (Zoloft), citalopram (Celexa) and escitalopram (Lexapro)

While some people gain weight after starting an antidepressant, the antidepressant isn't always a direct cause. There are many factors that can work together to contribute to weight gain during antidepressant therapy. For example:

• Overeating as a result of depression can cause weight gain.
• Some people lose weight as part of their depression. In turn, an improved appetite associated with improved mood may result in increased weight.
• Adults generally tend to gain weight each year, regardless of the medications they take. Getting regular exercise and watching what you eat will help you maintain a healthy weight whether you take an antidepressant or not.

If you gain weight after starting an antidepressant, discuss your concerns with your doctor. If your antidepressant seems to be the culprit, it may help to adjust the dose or switch medications.