A large UK study has revealed that different antidepressants can cause strikingly different side-effects, particularly when it comes to weight gain, 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 participants taking 30 types of antidepressants. They found that while some drugs can lead to significant physical changes within just eight weeks, others have minimal effects.
The study showed a 4kg difference in average weight change between certain drugs. People taking agomelatine tended to lose around 2.5kg, while those on maprotiline gained about 2kg. Nearly half of patients prescribed maprotiline or amitriptyline experienced weight gain, whereas more than half of those taking agomelatine lost weight.
Heart rate and blood pressure also varied notably — with a 21-beat-per-minute difference between fluvoxamine and nortriptyline users, and an 11 mmHg gap in blood pressure between nortriptyline and doxepin.
Dr Toby Pillinger of King’s College London said the findings highlight the need for more personalised antidepressant care. “While many people benefit, these drugs are not identical. Some can cause meaningful physical changes in a short period,” he said.
The researchers urged the update of clinical guidelines to better reflect these differences and called for shared decision-making between patients and doctors to help tailor treatments based on personal needs and side-effect risks.
