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If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.
If you’ve been prescribed an antidepressant, you may be curious about its potential effect on weight, particularly if it causes weight gain or weight loss. While many antidepressants have been shown to potentially cause weight gain, there’s only one that is known to cause weight loss in the long run. Here’s what the research says about how antidepressant use can affect what you see on the scale.
Do some antidepressants cause weight loss?
There are more than a dozen antidepressant drugs that are popularly prescribed. But only one has been consistently associated with weight loss in studies: bupropion (brand name Wellbutrin; see Important Safety Information).
A 2019 meta-analysis of 27 studies on antidepressants and weight gain found that taking antidepressants can increase body weight by an average of 5%—except bupropion, which was associated with weight loss (Alonso-Pedrero, 2019).
Another study from 2016 looked at the long-term weight loss effect of various antidepressants and found that non-smokers who took bupropion lost 7.1 pounds over two years. (This effect was not seen in smokers.) Users of the other antidepressants in the study gained weight (Arterburn, 2016).
Bupropion also seems to help with weight loss maintenance. A 2012 study found that adults with obesity who took bupropion SR (standard release) in 300mg or 400mg doses lost 7.2% and 10% of their body weight, respectively, over 24 weeks and maintained much of that weight loss at 48 weeks (Anderson, 2012).
In fact, bupropion is part of the popular weight loss drug naltrexone-bupropion (brand name Contrave), which is FDA approved for treatment of overweight or obesity.
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Why do antidepressants affect weight?
Experts aren’t exactly sure why weight changes occur with antidepressants. Antidepressant medications’ effect on weight is, in the words of one study, “only partially understood” and “poorly described” (Gafoor, 2018).
In very broad terms, antidepressants act on a variety of chemicals, neurotransmitters, and receptors in the brain. This changes the level of the impact of these neurotransmitters in the brain. Ideally, that improves mental health issues like depression and anxiety. In some cases, these effects seem to cause metabolic changes that lead to weight gain.
For example: Bupropion is a medication known as an NDRI (norepinephrine-dopamine reuptake inhibitor). This means that it prevents the brain from absorbing free-floating norepinephrine and dopamine (two types of neurotransmitters). When they aren’t reabsorbed quickly, adrenaline and dopamine stick around and act on the brain longer. This may affect metabolism and appetite, resulting in weight loss.
Some antidepressants affect histamine and serotonin, which regulate appetite (Gill, 2020). Others act on neurotransmitters and receptors connected to weight gain (David, 2016). Some of these medications, mainly the early first-generation tricyclic antidepressants, may change the way the body metabolizes lipids (fats) and glucose (blood sugar) (Hasnain, 2012; David, 2016).
Of course, weight gain or weight loss is far from guaranteed when you take antidepressants.
Fear of weight gain shouldn’t keep you from taking antidepressants if you need them. Talk with your healthcare provider if you’re bothered by weight changes—adjusting your diet, increasing exercise, or, in some cases, switching medications can be effective solutions.
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What types of antidepressants are available?
There are many different types of antidepressants available.
The most common antidepressant medications are selective serotonin reuptake inhibitors (SSRIs), which include fluoxetine (brand name Prozac; see Important Safety Information), sertraline (brand name Zoloft; see Important Safety Information), paroxetine (brand name Paxil or Brisdelle; see Important Safety Information), and escitalopram (brand name Lexapro; see Important Safety Information).
Serotonin-norepinephrine reuptake inhibitors (SNRIs) are also frequently prescribed, including venlafaxine (brand name Effexor; see Important Safety Information), duloxetine (brand name Cymbalta; see Important Safety Information), and desvenlafaxine (brand name Pristiq).
Bupropion, as we’ve discussed, is an NDRI, so it works a little differently than the more standard SSRIs and SNRIs.
Other types of antidepressants include tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors. These tend to cause worse side effects, so they’re not generally the first treatment your provider will try.
Additional treatments for depression
In some cases, depression can have a medical cause, such as hypothyroidism, vitamin B12 deficiency, low testosterone, or side effects of medication. A healthcare provider can diagnose and treat these.
Unfortunately, most cases of depression aren’t caused by medical issues. For depression that doesn’t have a medical cause, the main treatments are antidepressant medication and psychotherapy.
Research shows that antidepressants and cognitive behavioral therapy (CBT) are about equally effective for the treatment of depression. However, CBT may have more long-lasting effects and prevent relapse (Hollon, 2005). During CBT, therapists encourage patients to replace negative, unhelpful thoughts with more positive ones.
Cognitive-behavioral therapy (CBT): what is it and what does it work for?
Diet and exercise
Both aerobic and resistance exercises have been found to be effective at relieving depression (Craft, 2004). Some studies indicate that the Mediterranean diet is associated with a lower rate of depression (Sánchez-Villegas, 2009).
Other things that might improve depression include getting better sleep, increasing social interaction, and avoiding excessive alcohol and tobacco use.
Seek the help you need
If you are feeling anxious or depressed, it’s important to seek out the help you need. Speak with your healthcare provider or a mental health professional to figure out whether antidepressants, therapy, or a combination thereof are right for you. If you are concerned about weight gain or weight loss on antidepressants, be sure to discuss that with your healthcare provider as well. Together, you can determine a treatment approach that’s best for you.
- Alonso‐Pedrero, L., Bes‐Rastrollo, M., & Marti, A. (2019). Effects of antidepressant and antipsychotic use on weight gain: A systematic review. Obesity Reviews : An Official Journal of the International Association for the Study of Obesity, 20(12), 1680–1690. doi: 10.1111/obr.12934. Retrieved from https://pubmed.ncbi.nlm.nih.gov/31524318/
- Anderson, J. W., Greenway, F. L., Fujioka, K., Gadde, K. M., McKenney, J., O’Neil, P. M. (2012). Bupropion SR Enhances Weight Loss: A 48-Week Double-Blind, Placebo- Controlled Trial. Obesity Society, 10(7), 633-641. https://doi.org/10.1038/oby.2002.86. Retrieved from https://onlinelibrary.wiley.com/doi/full/10.1038/oby.2002.86
- Arteburn, D., Sofer, T., Boudreau, D. M., Bogart, A., Westbrook, E. O., Theis, M. K., et al. (2016). Long-term weight changes after initiating second-generation antidepressants. Journal of Clinical Medicine, 5(4):48. doi: 10.3390/jcm5040048. Retrieved from https://pubmed.ncbi.nlm.nih.gov/27089374/
- Craft, L. L., & Perna, F. M. (2004). The Benefits of Exercise for the Clinically Depressed. The Primary Care Companion to The Journal of Clinical Psychiatry, 06(03), 104–111. doi: 10.4088/pcc.v06n0301. Retrieved from https://pubmed.ncbi.nlm.nih.gov/15361924/
- David, D. J., & Gourion, D. (2016). Antidépresseurs et tolérance : déterminants et prise en charge des principaux effets indésirables [Antidepressant and tolerance: Determinants and management of major side effects]. L’Encephale, 42(6), 553–561. https://doi.org/10.1016/j.encep.2016.05.006. Retrieved from https://pubmed.ncbi.nlm.nih.gov/27423475/
- DSM-5 (2013). Depressive disorders. Diagnostic and Statistical Manual of Mental Disorders. doi:10.1176/appi.books.9780890425596.dsm04. Retrieved from https://dsm.psychiatryonline.org/doi/book/10.1176/appi.books.9780890425596
- Gafoor, R., Booth, H. P., & Gulliford, M. C. (2018). Antidepressant utilisation and incidence of weight gain during 10 years’ follow-up: population based cohort study. BMJ (Clinical Research Ed.), 361, k1951. https://doi.org/10.1136/bmj.k1951. Retrieved from https://pubmed.ncbi.nlm.nih.gov/29793997/
- Gill, H., Gill, B., El-Halabi, S., Chen-Li, D., Lipsitz, O., Rosenblat, J. D., et al. (2020). Antidepressant Medications and Weight Change: A Narrative Review. Obesity, 28(11), 2064–2072. doi: 10.1002/oby.22969. Retrieved from https://onlinelibrary.wiley.com/doi/abs/10.1002/oby.22969
- Hasnain, M., Vieweg, W. V., & Hollett, B. (2012). Weight gain and glucose dysregulation with second-generation antipsychotics and antidepressants: a review for primary care physicians. Postgraduate Medicine, 124(4), 154–167. https://doi.org/10.3810/pgm.2012.07.2577. Retrieved from https://pubmed.ncbi.nlm.nih.gov/22913904/
- Hollon, S. D., Derubeis, R. J., Shelton, R. C., Amsterdam, J. D., Salomon, R. M., O’Reardon, J. P., et al. (2005). Prevention of Relapse Following Cognitive Therapy vs Medications in Moderate to Severe Depression. Archives of General Psychiatry, 62(4), 417. doi: 10.1001/archpsyc.62.4.417. Retrieved from https://pubmed.ncbi.nlm.nih.gov/15809409/
Dr. Steve Silvestro is a board-certified pediatrician and Senior Manager, Medical Content & Education at Ro.