A major UK study has found that different antidepressants can produce strikingly different side effects, including weight changes, heart rate fluctuations, and variations in blood pressure.
Researchers from King’s College London and the University of Oxford analysed data from 151 clinical trials involving more than 58,000 people taking 30 types of antidepressants. They discovered that some medications could cause up to 2kg of weight gain within two months, while others were linked to similar levels of weight loss.
For example, patients on maprotiline gained about 2kg on average, while those taking agomelatine lost around 2.5kg. Nearly half of patients on drugs like maprotiline or amitriptyline experienced weight gain, whereas more than half of agomelatine users lost weight.
The team also reported notable cardiovascular differences — with up to a 21 beats-per-minute variation in heart rate and an 11 mmHg difference in blood pressure between certain drugs.
Dr Toby Pillinger of KCL said the findings highlight how antidepressants “are not identical” and that some “can lead to meaningful changes in weight, heart rate, and blood pressure in a short period.” He added that while SSRIs generally have fewer physical side effects, closer monitoring may be needed for others.
Professor Andrea Cipriani from Oxford said the results underline the importance of shared decision-making between doctors and patients, ensuring treatments are tailored to individual health profiles and preferences.
