A significant new review has revealed that commonly prescribed antidepressants may be putting millions of patients at increased risk of weight gain, hypertension, and heart problems. British neuroscientists, reviewing data from over 58,500 participants and comparing 30 different antidepressants, found notable differences in their physiological effects, particularly concerning cardiovascular health. This prompts doctors to reconsider prescription practices and enhance patient monitoring.

The review highlighted amitriptyline, a tricyclic antidepressant, as a drug with significant physiological impacts. It was found to cause weight gain in nearly half of prescribed patients, an increased heart rate, and heightened blood pressure. Specifically, patients on amitriptyline gained 1.5kg after just eight weeks, experienced a 9 beats per minute (bpm) increase in heart rate, and a 5mmHg rise in systolic blood pressure. These changes escalate the risk of stroke by 5% and the risk of all-cause death by almost 10%. Furthermore, nortriptyline, another antidepressant, was associated with an increase in heart rate of over 13 bpm.

Other antidepressants identified as significantly increasing weight gain included mirtazapine and several other tricyclic antidepressants. The researchers, led by academics at King's College London, observed a 4kg difference in weight change depending on the prescribed drug. Strong evidence also suggested increases in blood pressure with serotonin-noradrenaline reuptake inhibitors (SNRIs) like duloxetine, as well as with amitriptyline.

Conversely, the review offered some reassurance regarding selective serotonin reuptake inhibitors (SSRIs), the most prescribed type of antidepressant. Patients on citalopram, a common SSRI, saw an average weight loss of around 0.65kg and decreases in heart rate and systolic blood pressure, though a slight increase in diastolic blood pressure was noted. Dr. Toby Pillinger, a consultant psychiatrist and senior author of the study, emphasized that while many benefit from antidepressants, their effects are not uniform, and some can lead to meaningful physical changes in a relatively short period, warranting closer physical health monitoring for certain drugs.

The findings come amidst a rising trend in antidepressant prescriptions, with an estimated 8.8 million people in England taking these drugs, accounting for about one in seven individuals. In 2024-25 alone, over 92 million antidepressant prescriptions were issued in England. Given the prevalence, experts are calling for updated guidelines and routine physical health checks. Dr. Prada Nishtala, an expert in pharmacoepidemiology, stressed that given patients often take antidepressants for extended periods, cumulative risks are likely higher, particularly for those with chronic depression or existing metabolic conditions. She advocates for incorporating antidepressants into the UK's QRISK assessment, which estimates a patient's 10-year risk of heart attack or stroke, to better reflect the metabolic burden of psychiatric pharmacotherapy and support personalized prescribing.

Professor Andrea Cipriani from the University of Oxford, a study co-author, highlighted the importance of 'shared decision making' in treatment choices, where patients' preferences, circumstances, and values are collaboratively integrated with clinical guidance. However, some experts urge caution. Professor Frank Moriarty advised patients not to stop medication without consulting a medical professional, noting that the study focused solely on physical side effects and did not assess benefits or withdrawal effects. The researchers' overarching aim is not to deter antidepressant use but to empower patients and clinicians to make informed choices and encourage personalized care. The Medicines and Healthcare products Regulatory Agency (MHRA) reassures patients that all known side effects are detailed in product information leaflets, advising anyone with concerns to speak to a healthcare professional, who may offer alternative doses, different drugs, or additional medication to manage side effects, and to report suspected side effects via the Yellow Card scheme.