Some Antidepressants Linked to More Weight Gain Than Others

3 min read

July 2, 2024 – More than 1 in 10 people in the U.S. take antidepressant medications, although many people discontinue the drugs due to an array of side effects, including weight gain. But recent insights show that some antidepressants are linked to an increased chance of weight gain, compared to others. 

The findings of  a large new analysis from Harvard researchers could help guide treatment decisions to make people more likely to stay on the medicines and, ultimately, benefit from them. The new information is also important for people who want to take antidepressants but need to manage their weight due to conditions such as diabetes.

Published this week in the journal Annals of Internal Medicine, the analysis included health records from more than 180,000 people ranging in age from 18 to 80 years old. The people were considered first-time users of antidepressants, and the researchers analyzed weight changes after 6, 12, and 24 months on the medicines. Eight drugs were evaluated, known by the brand names Celexa, Cymbalta, Effexor, Lexapro, Paxil, Prozac, Wellbutrin, and Zoloft. The results included people who took brand-name or generic versions of the drugs.

People taking Wellbutrin were the least likely to gain weight. Wellbutrin users were about 15% less likely to gain weight, compared to people taking Zoloft, which is the most commonly prescribed antidepressant. Weight gain was defined as an increase of 5% or more from a person’s weight when starting the medication.

The researchers noted that previous research had documented the low likelihood of weight gain among people taking Wellbutrin. They wrote that it may be related to Wellbutrin’s impact on neurotransmitters known as dopamine and norepinephrine, and the drug’s effects on a brain system called the hypothalamic melanocortin system, which is involved in appetite and energy balance.

People who took Celexa, Cymbalta, Effexor, Lexapro, or Paxil gained more weight on average, compared to people who took Zoloft. Taking Cymbalta, Lexapro, or Paxil was linked to a 10% to 15% higher risk of weight gain.

In 2020, 18% of U.S. adults reported having ever been diagnosed with depression. Antidepressants are also commonly prescribed for people with other conditions, like anxiety or bipolar disorder.

Depression includes a wide range of life-altering symptoms, such as persistent sad or anxious moods, low energy, poor sleep, and physical changes. Not everyone with depression has suicidal thoughts, but the condition is linked to a significantly heightened risk of having thoughts and ideas about suicide.

Antidepressants work by changing the way the brain relays messages that can impact depression’s wide range of symptoms, from mood to appetite to sleep.

The researchers reported that more than half the people stopped taking the medications, no matter the brand, by the 6-month mark. Wellbutrin and its generic version had the highest 6-month adherence rate, at 41%.

“Patients and their clinicians often have several options when starting an antidepressant for the first time. This study provides important real-world evidence regarding the amount of weight gain that should be expected after starting some of the most common antidepressants,” lead study author Joshua Petimar, ScD, an assistant professor of population medicine at Harvard Medical School and the Harvard Pilgrim Health Care Institute, said in a statement. “Clinicians and patients can use this information, among other factors, to help decide on the right choice for them.”

If you or someone you care about is struggling, help is available 24/7 by calling or texting the Suicide and Crisis Lifeline at 988.