New research has highlighted a significant concern for patients using certain antidepressants: increased weight gain. The study, published in the Annals of Internal Medicine, analyzed data from 183,118 patients across eight U.S. health systems between 2010 and 2019. It found that some antidepressants are more likely to be associated with weight gain than others.
At the six-month mark, patients using escitalopram (Lexapro), paroxetine (Paxil), and duloxetine (Cymbalta) were 10% to 15% more likely to gain at least 5% of their baseline weight compared to those using sertraline (Zoloft). Conversely, patients using bupropion (Wellbutrin) were 15% less likely to gain weight than those on sertraline, while fluoxetine (Prozac) showed no significant association with weight change.
Lead author Joshua Petimar, an assistant professor of population medicine at Harvard Medical School, emphasized the importance of these findings. “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,” Petimar said in a news release.
However, the study had some limitations, including inconsistent information on medication dosage and adherence. It was also observational, meaning it shows correlation but not causation. While the study indicates a correlation between certain drugs and weight gain, it doesn’t necessarily mean the drugs are directly causing the weight gain. For instance, if someone lost their appetite due to depression and then took medication that improved their symptoms, weight gain could follow without the drug being directly responsible. “It’s the treatment of the depression, and then subsequently, regain of appetite that’s causing a weight gain,” explained Dr. Aron Tendler, a psychiatrist and chief medical officer at BrainsWay, a health technology company.
The study also revealed significant discontinuation rates among patients. “In general, when someone’s prescribed a medicine, they really should be on it for a year,” Tendler said. “The amount of people that were discontinuing the medicines at three, six, and 12 months were incredibly high. Only about 4% of people stayed on their meds for 24 months.” While the odds of weight gain are “not terribly high,” Tendler noted, the major takeaway for patients and clinicians is that there are multiple options if someone is concerned about weight gain. “People can switch to other medications,” he said, which could help in better adherence and treatment outcomes. “There are also nonmedication treatments like transcranial magnetic stimulation (TMS)… I think people should be taking that into consideration.”
Government data from 2017 showed that antidepressant use rose 65% between 1999 and 2014. Recent studies have also shown the impact of the COVID-19 pandemic on increased antidepressant use among young people. For those aged 12 to 25, antidepressant use increased nearly 64% since the start of the pandemic, according to a study earlier this year.
The relationship between major depressive disorder (MDD) and obesity is complex and multifaceted. According to the World Health Organization (WHO), MDD has become the second most prevalent cause of illness-induced disability, affecting 350 million people worldwide. In the United States, costs related to MDD, including medical expenses, are estimated to be $210.5 billion a year. With a lifetime prevalence of 16.2%, MDD is twice as common in women, and two-thirds of suicides are associated with MDD.
Obesity, another significant public health issue, affects 34.9% of U.S. adults, resulting in estimated annual medical costs of $147 billion in 2008. The prevalence of obesity among adults has more than doubled since 1962, paralleling the increase in MDD treatment. Besides type 2 diabetes mellitus and cardiovascular diseases (CVDs), obesity has other disabling consequences, including cancer, sleep disorders, and psychological distress.
Studies have addressed the relationship between obesity and MDD, suggesting that both disorders share common pathophysiology to some extent. However, the precise pathways and mechanisms for a causal association between MDD and obesity remain unknown. In the United States, the rate of antidepressant use has increased nearly 400% over the past two decades. Antidepressant drugs were the third most prescribed class of drugs for persons aged 18-44 years in 2005–2008.
With the rapid rise of individuals taking antidepressants, numerous studies have investigated the effects of different classes of antidepressants on body weight. Despite the frequent use of antidepressants and the high incidence of obesity in Western societies, the pathways and mechanisms by which antidepressants can induce weight gain remain unclear.
The diagnosis of MDD is made in the presence of five or more symptoms for a continuous two-week period or longer, as described in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). These symptoms include depressed mood, significant weight loss or gain, diminished interest in activities, insomnia or hypersomnia, fatigue, psychomotor retardation or agitation, feelings of worthlessness, diminished ability to concentrate, and recurrent thoughts of death.
The pathophysiology of MDD is complex and not fully understood. Theories include the monoamine depletion hypothesis, neuroendocrine theory, neuroimmune theory, and neurotropic hypothesis. These theories suggest that various factors, including abnormal homeostasis of the hypothalamus-pituitary-adrenal (HPA) axis, immune mediators, and neurotropic factors, play a role in MDD.
Obesity is primarily defined as an excess of fat mass that produces adverse health consequences. It is diagnosed based on body mass index (BMI), with a BMI of 30 kg/m2 and over indicating obesity. The causes of obesity are complex and include environmental, genetic, cultural, food choices, and hormonal factors.
Obesity and MDD frequently co-exist, causing substantial health problems. Both disorders can lead to CVD, and genetic polymorphisms may underlie the predisposition to both CVD and depression. Studies have shown that obesity is positively associated with MDD, and vice versa. Cross-sectional and longitudinal studies have indicated that obesity increases the risk of developing MDD, and MDD can lead to obesity.
In conclusion, the recent study on antidepressants and weight gain provides valuable insights for patients and clinicians. While some antidepressants are associated with increased weight gain, others are not, offering options for those concerned about this side effect. Understanding the complex relationship between MDD and obesity is crucial for developing effective treatment strategies.
Source: CBS News, Annals of Internal Medicine
