Antidepressants Make You Gain Weight

Analyzing data from the REGICOR study (Registre Gironí del Cor) over more than six years, researchers observed an average 2% weight increase in all participants who used antidepressants at any point. These findings highlight the need to consider alternative approaches to treating depression beyond medication alone, the journal Frontiers in Psychiatry reported.

Individuals taking antidepressants gained approximately 2% more weight than those who did not.

This weight increase was observed regardless of when participants started or stopped taking the medication.

Researchers emphasize the importance of exploring non-pharmacological treatments for depression.

A recent study by the Hospital del Mar Research Institute, published in Frontiers in Psychiatry, highlights a clear link between antidepressant use and weight gain. Using data from the REGICOR study (Registre Gironí del Cor), researchers found that individuals taking antidepressants experienced an average 2% increase in body weight.

The study, the first of its kind conducted in Spain, included experts from multiple institutions, including CIBER for Pathophysiology of Obesity and Nutrition (CIBEROBN), CIBER for Cardiovascular Diseases (CIBERCV), Ramon Llull University, the University of Vic-Central University of Catalonia, University College London, IDIAP Jordi Gol, and the Girona Biomedical Research Institute Dr. Josep Trueta (IdIBGi).

Tracking 3,127 adults over six years — 1,700 of them women, with an average age of 55 — the study examined patterns of antidepressant use. About 16.4% of participants reported taking antidepressants, with 5.1% using them consistently, 6.2% starting them during the study, and 5.1% discontinuing them. While all participants gained some weight (an average of half a kilogram), those on antidepressants saw a more significant increase.

“All individuals taking antidepressants had a higher likelihood of gaining weight and developing obesity. This risk is even greater for those who use these medications continuously,” explains Dr. Camille Lassale, a researcher at the Hospital del Mar Research Institute and the Barcelona Institute for Global Health (ISGlobal), a center supported by the la Caixa Foundation.

The study considered the well-known bidirectional relationship between depression and obesity, as well as other associated factors, such as poor adherence to healthy diets and lack of physical exercise. However, the link between antidepressant use and weight gain remained independent of age, sex, socioeconomic status, lifestyle, and the presence (or absence) of depressive symptoms.

Participants who took antidepressants at the beginning and later stopped experienced an additional 1.8% weight gain compared to those who never took them. Those who started antidepressants during the follow-up and those who continued taking them throughout the study gained 2% more weight. In the latter group, the risk of developing obesity doubled. Participants who used antidepressants continuously were more frequently women, older adults, and individuals with a less healthy lifestyle (diet and physical activity).

Gabriela Lugon, a researcher at Hospital del Mar and a resident physician in the Preventive Medicine and Public Health Teaching Unit at Hospital del Mar, Pompeu Fabra University, and the Barcelona Public Health Agency, highlights that these findings underscore the need to consider this association when prescribing antidepressants and to monitor weight changes accordingly.

“We cannot simply prescribe antidepressants for their positive effects without also considering this side effect,” Lugon states. For this reason, the authors of the study stress the importance of monitoring weight changes in individuals undergoing antidepressant treatment, along with other cardiometabolic health markers.

Dr. Víctor Pérez, head of the Psychiatry Department at Hospital del Mar, emphasizes that antidepressants are highly effective for treating some of the most common mental illnesses. However, “their effect on weight is not universal, although certain medications, such as mirtazapine and paroxetine, can cause significant weight gain.” He also warns that “due to the risk of patients discontinuing treatment because of weight gain, we must consider alternative therapeutic strategies to complement pharmacological treatment.”

Depression affects 280 million people worldwide and is the most prevalent mental disorder, impacting women twice as often as men. Weight gain is one of the main reasons why people discontinue treatment. At the same time, 650 million people worldwide suffer from obesity, highlighting the strong bidirectional relationship between these two conditions. Spain, along with Sweden and Portugal, has the highest antidepressant consumption rates in Europe.

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