Antidepressants and weight gain: What causes it?

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

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

• Some tricyclic antidepressants, such as amitriptyline, nortriptyline (Pamelor), imipramine and doxepin.
• Some monoamine oxidase inhibitors (MAOIs), such as phenelzine (Nardil).
• Paroxetine (Paxil), a selective serotonin reuptake inhibitor (SSRI).
• Mirtazapine (Remeron), which is an atypical antidepressant. Atypical means that the medicine doesn't neatly fit into another antidepressant group.

While some people gain weight after starting an antidepressant, the antidepressant isn't always a direct cause. Many factors can be part of weight gain during antidepressant therapy. For example:

• Some people gain weight because they eat too much or don't get enough physical activity because of depression.
• Some people lose weight as part of their depression. In turn, an improved appetite that's linked with improved mood may result in weight gain.
• Adults generally tend to gain weight as they age, no matter what medicines they take.

If you gain weight after starting an antidepressant, talk about the medicine's benefits and side effects with your doctor or other healthcare professional. If you're enjoying an improved mood due to the medicine, the benefits may outweigh the side effect of weight gain. Think about managing your weight through changes to your diet or level of physical activity. Talk with your healthcare professional about your diet and exercise habits. This can help you decide on your goals and make a plan for what you need to do to reach them.

You also can ask your healthcare professional about medicine changes that could help. Changing the dose of your current antidepressant, switching to a different antidepressant or adding a medicine may be an option. Talk about the pros and cons before making such a decision.

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