Antidepressants Linked to Physical Changes Within Weeks, Major Study Finds
A corner study published in The Lancet has revealed that certain antidepressants can bring about conspicuous physical changes such as shifts in weight, blood pressure, and heart rate, within just a matter of weeks.
The discovery has urged experts to call for a critical review of antidepressant treatment guidelines across the UK and beyond.
Antidepressants are among the most commonly prescribed medications in Europe and North America, with nearly one in five grown-ups taking them to manage conditions such as depression and anxiety.
While their cerebral goods have been considerably studied, the physical impact of these medicines has remained murkier, until now.
Researchers analyzed 151 separate studies, covering 30 different antidepressants and more than 58,000 patients. The results were striking.
Some medications were found to trigger significant physical alterations within just eight weeks of use.
For instance, participants taking maprotiline gained an average of 2 kilograms, whereas those using agomelatine experienced up to 2.5 kilograms of weight loss.
About 10-15% of the adult population takes antidepressants
The Lancet just published the first meta-analysis that shows how each affects physical health: metabolism, heart rate, kidney and liver function
This should help tailor antidepressant choice for individual people pic.twitter.com/ER3u09Eo75
— Samuel Hume (@DrSamuelBHume) October 22, 2025
That’s a 4-kilogram gap between the two treatments. Similarly, the study noted a 21-beat-per-minute difference in heart rate between fluvoxamine and nortriptyline.
By contrast, several SSRIs (Selective Serotonin Reuptake Inhibitors), the most prescribed class of antidepressants, showed minimal impact on body weight or cardiovascular measures.
Dr Toby Pillinger, Academic Clinical Lecturer at the Institute of Psychiatry, Psychology & Neuroscience, and Consultant Psychiatrist at the South London and Maudsley NHS Foundation Trust, emphasized the real-world significance of the findings.
“Antidepressants are among the most widely used medicines in the world. While many people benefit from them, these drugs are not identical – some can lead to meaningful changes in weight, heart rate, and blood pressure in a relatively short period.”
He continued: “Our findings show that SSRIs, which are the most prescribed type of antidepressant, tend to have fewer physical side effects, which is reassuring. But for others, closer physical health monitoring may be warranted.”
“The aim isn’t to deter use, but to empower patients and clinicians to make informed choices and to encourage personalized care.”
Professor Andrea Cipriani, Professor of Psychiatry at the University of Oxford and Director of the NIHR Oxford Health Clinical Research Facility, echoed this sentiment.
“Most clinical decisions, especially in mental health, are still made by physicians with little input from patients.”
“Our results emphasize the importance of shared decision making, the collaborative process through which patients are supported by the clinicians to reach a decision about their treatment, bringing together their preferences, personal circumstances, goals, values, and beliefs.
This should be the way forward in the NHS and globally.”
The findings have major implications for the NHS, where antidepressant prescriptions have continued to rise year on year.
With antidepressant side effects now shown to vary so widely, experts are urging GPs to adopt a more tailored approach, one that considers not just mood improvement, but also the potential physical toll of these drugs.
The study, supported by the National Institute for Health and Care Research (NIHR), Maudsley Charity, Wellcome Trust, and the Medical Research Council, marks a pivotal step towards more informed prescribing and patient-centered mental health care.
Antidepressants can do more than lift mood; they can shape the body, too. Some bring stability. Others bring change. And now, science is calling for balance, not just in the mind, but in the body as well.
