Lexapro, Paxil and Cymbalta carry a higher risk of packing on pounds than Zoloft, while Wellbutrin users are less likely to gain weight, according to a new study of eight popular antidepressants.

Harvard Pilgrim Health Care Institute (HPHCI) researchers analyzed the weights of more than 183,000 adult antidepressant users six months, a year and two years after they started taking the drugs.

Data from taking Celexa (citalopram), Lexapro (escitalopram), Prozac (fluoxetine), Paxil (paroxetine), Wellbutrin (bupropion), Cymbalta (duloxetine) and Effexor (venlafaxine) was compared to Zoloft (sertraline), which is the most prescribed antidepressant in the US.

At six months, Lexapro, Paxil and Cymbalta users were 10% to 15% more likely to gain at least 5% of their starting weight than Zoloft consumers.

Prozac was not associated with a six-month weight change, while Wellbutrin users were 15% less likely to experience a 5% weight gain. Wellbutrin continued to be associated with the least weight gain at the one- and two-year marks.

The findings were published this week in the Annals of Internal Medicine.

The researchers credited Wellbutrin’s ability to increase levels of dopamine and norepinephrine in the brain, which improve wakefulness and alertness.

The drug — used to treat depression and seasonal affective disorder and help people stop smoking — has also been shown to stimulate the central melanocortin system, which regulates appetite, energy balance and body weight.

The study results come amid growing antidepressant use, especially among young adults and teens.

One study found that about 14% of US adults take an antidepressant. The HPHCI researchers noted that people often stop using the drug if they experience weight gain.

“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,” said lead author Joshua Petimar, a Harvard Medical School assistant professor of population medicine.

“Clinicians and patients can use this information, among other factors, to help decide on the right choice for them,” he added.