Antidepressants May Raise Long-Term Weight Gain Risk

Antidepressant use is known to be associated with a short-term risk of weight gain, and new research suggests that it may be associated with a long-term risk weight gain risk as well.1

These findings warrant particular attention due to the known risks of chronic disease and mortality that are associated with overweight and obesity.2

To further evaluate the long-term effects of antidepressant use on the risk of weight gain, researchers evaluated 136,762 men and 157,957 women with at least 3 records for body mass index (BMI). Patient data were obtained from the UK Clinical Practice Research Datalink between 2004 and 2014.

The main outcomes of the study included antidepressant prescribing, incidence of at least 5% increase in body weight, and becoming overweight or obese.

A Poisson model was used to estimate adjusted rate ratios, and finding were adjusted for age, sex, depression recording, and comorbidity, among other factors.

A total of 17,803 men (13.0%) and 35,307 women (22.4%) had been prescribed antidepressants during the year of study entry. Over the course of 1,836,452 person-years of follow-up, the incidence of new episodes of at least 5% weight gain was found to be 11.2 per 100 person-years in antidepressant-treated participants and 8.1 per 100 person-years in those who were not prescribed antidepressants.

Weight gain risk appeared to remain elevated throughout at least 6 years of follow-up, the researchers wrote.

During year 2 of treatment, 27 participants were treated with antidepressants for 1 year for 1 additional episode of at least 5% weight gain.

Adjusted rate ratios were found to be 1.29 for participants who were initially of normal weight and transitioned to overweight or obesity, and 1.29 for participants who were initially overweight and transitioned to obesity.

However, the researchers noted, the associations observed in this study may not be causal, and residual confounding could contribute to overestimation of associations.

“Hopefully it will be possible in the not too distant future to identify a genetic predisposition and recognize those at higher risk before treatment is started,” researchers wrote in a separate editorial.2 “In these patients, we can then prescribe the antidepressant least likely to cause weight gain, monitor weight and metabolic variables carefully, and provide concomitant lifestyle advice to minimize weight gain.”

“Until then, we should give lifestyle advice and consider monitoring everyone taking these agents,” they concluded.

—Christina Vogt


1. Gafoor R, Booth HP, Gulliford MC. Antidepressant utilization and incidence of weight gain during 10 years’ follow-up: population based cohort study [Published online May 23, 2018]. BMJ. https://doi.org/10.1136/bmj.k1951

2. Serretti A, Porcelli S. Antidepressant induced weight gain [Published online May 23, 2018]. BMJ. https://doi.org/10.1136/bmj.k2151