Do antidepressants cause weight gain?

Weight gain has long been a common side effect of antidepressants, but some antidepressants are more likely to cause weight gain than others, according to a new study. New Research.

The study, published Monday in the journal Annals of Internal Medicine, analyzed electronic health records of more than 183,000 U.S. patients who were likely new to antidepressants and tracked their weight for 24 months.

After six months, patients who took Lexapro, Paxil, or Cymbalta had a 10 to 15 percent higher risk of clinically significant weight gain (defined as at least 5 percent of baseline weight) compared with those taking Zoloft. Patients who took Wellbutrin were less likely to experience this type of weight gain. The study included both brand-name and generic versions of each drug.

“Many patients worry that taking antidepressants will cause them to gain weight,” says Joshua Pettimer, M.D., assistant professor of population medicine at Harvard Medical School and Harvard Pilgrim Health Care Institute and lead author of the study. This may be especially true for patients with pre-existing conditions such as diabetes.

What's more, the weight gain can be so unsatisfying that some people stop taking their antidepressants even if they are effective, “which can again lead to a range of negative outcomes, including increased risk of hospitalisation and relapse,” Dr Pettimer said.

In the study, at six months, patients taking Lexapro or Paxil gained about a pound more on average than those taking Zoloft, the most commonly prescribed of the eight antidepressants tracked. People taking Cymbalta, Effexor, and Celexa also gained more weight initially than those taking Zoloft, but by less than a pound in each case. Meanwhile, patients taking Wellbutrin gained less weight than those taking Zoloft.

In the study, everyone who took the antidepressant experienced weight gain, and most of the people in the study were overweight or obese at the start. representative of the US population.

“It doesn't really matter which one you choose,” says Dr. David J. Hellerstein, a professor of clinical psychiatry at Columbia University Irving Medical Center, who was not involved in the study. “Whatever option you choose, the problem is the same.”

Choosing the right antidepressant is a matter of balancing efficacy with side effects, he adds, and deciding which side effects you can handle can be difficult.

For example, Wellbutrin users appear to be less likely to gain weight, but the drug “can make you feel very dry, and it has side effects like caffeine,” Dr. Hellerstein said. “Some people don't like that.”

Experts also said it's difficult to make broad generalizations about whether specific antidepressants cause weight gain, especially considering differences in diet, exercise, genetics and health history.

The study had several limitations. The researchers couldn't determine whether each patient was taking an antidepressant for the first time. Plus, the data didn't include consistent information about medication dosage, so the researchers couldn't determine how medication dosage affected weight gain.

Additionally, some people may have gained weight during the study even if they weren't taking the medication, Dr. Hellerstein said. If the study had included comparison subjects who weren't taking antidepressants, it might have helped determine the extent to which the medications affected weight gain, he added.

Some medications were associated with continued weight change over the two-year study period, while others showed a plateau, and more research is needed to see whether these curves can be replicated in future studies, Dr. Pettimer said.

“It gives rise to some interesting theories about why the orbits are different,” he added.