Public interest in antidepressant side effects has reached record levels, with Google searches for “antidepressants side effects” projected to rise by 203%, marking the highest peak worldwide in the past five years.
According to an analysis by dual diagnosis drug and alcohol treatment experts at Wellbrook Recovery, the surge coincides with the release of new research on the physical side effects of commonly prescribed antidepressants. Published in The Lancet, the study by King’s College London and the University of Oxford is the first to rank these drugs comparatively, revealing significant differences in how they affect the body.
The large-scale analysis examined data from 58,534 participants across more than 150 clinical trials and 17 US Food and Drug Administration reports. It focused on the first eight weeks of treatment, a period when side effects typically appear and influence adherence.
Findings showed that certain drugs can cause notable changes in weight, heart rate, and blood pressure. Amitriptyline, prescribed to 2.2 million patients in England in 2024/25, was linked to weight gain of up to 1.6kg on average, heart rate increases of up to nine beats per minute, and higher systolic and diastolic blood pressure. These effects can elevate cardiovascular risks, as even small weight increases can contribute to heart disease. Although amitriptyline is used for pain management and migraine prevention, the National Institute for Health and Care Excellence does not recommend it as a first-line treatment for depression, preferring selective serotonin reuptake inhibitors (SSRIs).
By contrast, SSRIs such as sertraline and citalopram showed more favourable outcomes. Sertraline, prescribed to 2.9 million patients last year, was associated with average weight loss of 0.76kg and a reduction in heart rate by two beats per minute, although it slightly raised blood pressure. Citalopram, used by 1.4 million patients, was linked to 0.65kg weight loss, a fall in heart rate and systolic blood pressure, and a minor rise in diastolic pressure. Overall, SSRIs demonstrated fewer physical side effects, supporting their widespread use among the eight million UK adults currently taking antidepressants.
Researchers also observed wide variations across drug types. Nortriptyline increased heart rate by 13.8 beats per minute, while fluvoxamine reduced it by eight, representing a 21-beat difference. Weight changes ranged from gains of nearly 2kg with some tricyclics to modest losses with SSRIs. Most drugs showed minimal effects on kidney and liver function, electrolytes, or heart rhythm, though the study underscored the importance of tailoring prescriptions to individual patient needs.
Dr Toby Pillinger, senior author and academic clinical lecturer at King’s College London’s Institute of Psychiatry, Psychology and Neuroscience, explained: “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 added that SSRIs’ lower risks are reassuring, though closer monitoring may be needed for others.
Professor Andrea Cipriani of the University of Oxford, the study’s last author, highlighted the importance of patient participation in treatment: “Most clinical decisions – especially in mental health – are still made by physicians with little input from patients. Our results emphasise the importance of shared decision making.”
In the UK, where one in six adults uses antidepressants, experts have called for more routine physical health checks. Professor Kamila Hawthorne, chair of the Royal College of GPs, said that prescriptions are issued for “good reason” and that follow-ups are usually arranged after two to three weeks to monitor effects.
Wellbrook Recovery reported that searches for “antidepressants side effects” rose 1,329% globally in the week following the study’s publication and 233% over the past year. Meir Kasnett, CEO of Wellbrook Recovery, said: “This groundbreaking research has revealed some shocking stats on the possible physical effects that common antidepressant drugs can have on people, so it’s to be expected that those who are prescribed these medications, or those who know someone who is, would be concerned.” He stressed that while not everyone experiences side effects, patients should remain informed and consult healthcare providers rather than abruptly stopping treatment.
Researchers are now developing a free online tool to help doctors and patients compare antidepressants based on individual health profiles. Professor Oliver Howes, a co-author of the study, stated: “There are big differences between these drugs and this is important not just for individual patients, but large numbers of people are taking them, so even modest changes could have a big effect across the whole population.”
Dr Frank Moriarty, associate professor at the Royal College of Surgeons in Ireland, described the findings as “novel and valuable”, noting that they could support more informed prescribing and patient choice.
