A large UK study has revealed that antidepressants vary widely in their physical side-effects, with some causing weight gain and others leading to weight loss or changes in heart rate and blood pressure.
Researchers from King’s College London and the University of Oxford analysed data from 151 clinical trials involving more than 58,000 patients across 30 antidepressant drugs. They found differences of up to 4kg in average weight change between medications — ranging from an average 2.5kg weight loss with agomelatine to about 2kg gain with maprotiline.
Nearly half of patients on maprotiline or amitriptyline gained weight, while over half of those on agomelatine lost weight. The study also noted a 21 beats-per-minute difference in heart rate between fluvoxamine and nortriptyline, and an 11 mmHg difference in blood pressure between nortriptyline and doxepin.
Dr Toby Pillinger of KCL said the results show antidepressants are “not identical” and that some “can lead to meaningful physical changes in a short period.” He noted that SSRIs, the most commonly prescribed type, tend to have fewer side-effects.
Co-author Prof Andrea Cipriani from Oxford said the findings highlight the need for “shared decision-making,” ensuring treatment choices reflect each patient’s preferences and circumstances.
Researchers have called for treatment guidelines to be updated so patients can make more informed choices about antidepressant use.
