The research, published today, outlines how different drugs affect weight, heart rate and blood pressure.
Experts at King’s College London analysed data from over 58,000 people across 150 clinical trials, comparing 30 antidepressants with placebos during the first eight weeks of treatment.
The study, published in The Lancet this morning, revealed that some antidepressants were linked to weight gain of up to 2kg in the first two months, while others were associated with weight loss of more than 2.4kg.
Sertraline, the most prescribed antidepressant in England, was associated with slight weight loss and a drop in heart rate. In contrast, amitriptyline, taken by over two million patients last year, led to average weight gain and a notable increase in heart rate and blood pressure.
The research couldn’t have been published at a better time. Figures show over 92 million antidepressant prescription were issued in England during 2024-25, covering an estimated 8.89 million people. With such widespread use, researchers claim the findings should inform routine physical health checks and spark conversations about side effects between patients and healthcare professionals.
‘Antidepressants are among the most widely used medicines in the world,’ said Dr Toby Pillinger, the study’s senior author. ‘While many people benefit, some drugs can lead to meaningful changes in weight, heart rate, and blood pressure even in a short period. The aim isn’t to deter use, but to empower patients and clinicians to make informed choices.’
Echoing a similar tone, Professor Azeem Majeed, chairman of primary care and public health at Imperial College London, said: ‘For patients and clinicians, the results underscore the need for routine physical health checks in those treated with antidepressants.
‘Moreover, awareness of these side effects is essential to support shared decision-making about the risks and benefits of treatment with antidepressants.’
Dr Lade Smith, president of the Royal College of Psychiatrists, added: ‘Antidepressants play a key role in the treatment of more severe depression and are particularly effective when used in combination with talking therapies.’
‘As with all drugs, antidepressants have side effects, and we very much welcome this study which helps improve our understanding of some of the physical side effects that can be caused by different types of antidepressants,’ Dr Smith continued. ‘These findings will help patients and clinicians choose the medication that is best suited to their personal needs.’
The authors of the study have emphasised the importance of personalised care and patient involvement. Professor Andrea Cipriani, co-author from the University of Oxford, said: ‘Our results emphasise 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.’
Despite the publication of the study, which can be accessed in full here, people taking antidepressants have been advised to not stop taking their medication without consulting a healthcare professional.
Photo by Nastya Dulhiier via UnSplash
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