Do antidepressants cause weight gain?

Samir Kadri
Author: Samir Kadri Medical Reviewer: Morgan Blair Last updated:

Weight gain can be a common side effect of both acute and long-term usage of antidepressants. [1] While each person responds to antidepressants differently, some antidepressant medications are more likely to cause weight gain than others.

Although some selective serotonin reuptake inhibitors (SSRIs) may cause weight loss during the early stages of therapy, this weight is often regained after 6 months and followed by increased weight gain with long-term use. [2]

Antidepressant use has risen exponentially across the United States for the past 6 years. [3] Their benefits for treating depression and a range of other mental health conditions are well established.

Weighing up these benefits against the potential side effects, such as weight gain, is a process you must go through with your healthcare provider. Together, you can work out which antidepressant best suits your needs and what dosage to take.

Do antidepressants cause weight gain?

What antidepressants can cause weight gain?

There are five classes of antidepressants – tricyclic antidepressants (TCAs), monoamine oxidase inhibitors (MAOIs), SSRIs, serotonin–norepinephrine reuptake inhibitors, and atypicals. [4]

It’s important to emphasize that individual responses to medications can vary, and not everyone taking these antidepressants will experience weight gain. Moreover, some individuals may experience weight loss or no significant change in weight while on these medications.

That said, the following antidepressants are more commonly associated with weight gain: [4]

Tricyclic antidepressants (TCAs)

TCAs have been prescribed since the 1950s and are the antidepressants most associated with weight gain. [4] They are not as heavily prescribed anymore due to the side effects they cause, but

Examples of TCAs include:

  • Amitriptyline (Elavil)
  • Nortriptyline (Pamelor)
  • Amoxapine
  • Desipramine (Norpramin)
  • Imipramine (Tofranil)
  • Protriptyline
  • Trimipramine

Monoamine oxidase inhibitors (MAOIs)

MAOIs, like TCAs, were a pioneering antidepressant prescribed to treat depression. Like, TCAs they are more likely to cause weight gain than SSRIs or most newer antidepressants [1] except for mirtazapine, which has been associated with weight gain. [5]

MAOIs are effective, but due to the side effects they cause, are considered a second or third of line treatment for depression and other mental health conditions [6].

Examples include:

  • Phenelzine (Nardil)
  • Tranylcypromine (Parnate)
  • Lisocarboxazid (Marplan)

Selective serotonin reuptake inhibitors (SSRIs)

SSRIs are the most widely prescribed antidepressants. These antidepressants are considered less likely to cause significant weight gain than TCAs and MAOIs. In fact, some studies have reported certain SSRIs, such as fluvoxamine, fluoxetine, and sertraline to be weight-neutral.

However, despite SSRIs being associated with weight loss in short-term use, long-term use of SSRIs is linked with a higher risk of weight gain. [8]

Commonly used SSRIs include:

  • Sertraline (Zoloft)
  • Fluoxetine (Prozac)
  • Paroxetine (Brisdelle, Paxil, Pexeva)
  • Citalopram (Celexa)

Atypical antidepressants

Atypical antidepressants are the newest variety of antidepressants, with different ways of acting on the body. [4]

Mirtazapine is an atypical antidepressant associated with weight gain over both short-term and long-term use. [4] [5]

What causes weight gain in antidepressant users?

It is not known exactly what causes weight gain in antidepressant users, although several factors are thought to play a role.

The association between antidepressant use and weight gain is primarily seen among people with unhealthy lifestyles, including Western dietary preferences, sedentary activity, and smoking. [7]

Depression may cause fluctuations in weight in people. It can cause fatigue and inactivity and this lack of movement could contribute to weight gain. Depression has also been associated with a reduced or increased appetite in individuals who are suffering.

Antidepressants affect the amount of serotonin, a neurotransmitter in your brain that aids in the regulation of mood. These changes may trigger cravings for carbohydrates and sugary foods, which when consumed in excess can be associated with weight gain.

Genetic factors can play a role in determining how someone responds to antidepressants. Some individuals may be more prone to weight gain because of their body’s specific reaction to the medication.

How to deal with weight gain from antidepressants

While some antidepressants lead to weight gain in patients, they are effective at treating depression and many other mental health conditions.

Getting assessed by a doctor and being frank about the symptoms you are experiencing are the first steps towards finding the right antidepressant for you.

Let your doctor know if you are experiencing any side effects, such as weight gain, and together you can weigh up the risks versus the benefits of continuing the medication.

A doctor may adjust your dose, switch you to a different antidepressant, or suggest other self-care treatments you can implement. Do not alter or switch your dose without speaking to a doctor, as this can cause adverse side effects.

For some people, implementing an exercise regime and engaging in a healthier lifestyle can stunt weight gain. Consult your doctor about any changes you make to your diet or exercise regime during a course of antidepressants.

  1. Fava, M. (2000). Weight gain and antidepressants. The Journal of Clinical Psychiatry, 61 Suppl 11, 37–41.
  2. Ferguson, J. M. (2001). SSRI Antidepressant Medications: Adverse Effects and Tolerability. Primary Care Companion to the Journal of Clinical Psychiatry, 3(1), 22–27.
  3. Wehrwein, P. (2011, October 20). Astounding increase in antidepressant use by Americans. Harvard Health Blog.
  4. Wharton, S., Raiber, L., Serodio, K., Lee, J., & Christensen, R. A. (2018). Medications that cause weight gain and alternatives in Canada: a narrative review. Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy, Volume 11, 427–438.
  5. Laimer, M., Kramer-Reinstadler, K., Rauchenzauner, M., Lechner-Schoner, T., Strauss, R., Engl, J., Deisenhammer, E. A., Hinterhuber, H., Patsch, J. R., & Ebenbichler, C. F. (2006). Effect of mirtazapine treatment on body composition and metabolism. The Journal of Clinical Psychiatry, 67(3), 421–424.
  6. Fiedorowicz, J. G., & Swartz, K. L. (2004). The role of monoamine oxidase inhibitors in current psychiatric practice. Journal of Psychiatric Practice, 10(4), 239–248.
  7. Shi, Z., Atlantis, E., Taylor, A. W., Gill, T. K., Price, K., Appleton, S., Wong, M.-L., & Licinio, J. (2017). SSRI antidepressant use potentiates weight gain in the context of unhealthy lifestyles: results from a 4-year Australian follow-up study. BMJ Open, 7(8).
  8. Lee, S. H., Paz-Filho, G., Mastronardi, C., Licinio, J., & Wong, M-L. (2016). Is increased antidepressant exposure a contributory factor to the obesity pandemic? Translational Psychiatry, 6(3), e759–e759.
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Samir Kadri
Author Samir Kadri Writer

Samir Kadri is a medical writer with a non-profit sector background, committed to raising awareness about mental health.

Published: Oct 17th 2023, Last edited: Oct 17th 2023

Morgan Blair
Medical Reviewer Morgan Blair MA, LPCC

Morgan Blair is a licensed therapist, writer and medical reviewer, holding a master’s degree in clinical mental health counseling from Northwestern University.

Content reviewed by a medical professional. Last reviewed: Oct 17th 2023