In a recent study, researchers have evaluated antidepressants based on various side effects experienced during the initial eight weeks of treatment. This research, spearheaded by experts from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King”s College London, analyzed data from over 58,000 participants involved in more than 150 studies that compared 30 different antidepressants to a placebo.
The study, published in The Lancet, highlighted significant differences in weight changes, heart rate, and blood pressure associated with these medications. Researchers indicated that these findings are intended to empower patients, advising them to consult healthcare professionals if they have any concerns about their treatment.
In the 2024/25 period, approximately 92.6 million antidepressants were prescribed to about 8.89 million patients across England. According to the NHS Business Services Authority, the antidepressant sertraline, also known as Lustral, was prescribed to nearly 2.9 million patients last year. This medication was associated with an average weight loss of 0.76 kg and a reduction in heart rate by two beats per minute, although it was also linked to slight increases in both systolic and diastolic blood pressure.
Another commonly prescribed drug, amitriptyline, was administered to approximately 2.2 million patients in England during the same period. This tricyclic antidepressant was linked to an average weight gain of 1.6 kg and an increase in heart rate by nine beats per minute, alongside rises in both blood pressure measurements. The NICE guidelines typically recommend trying selective serotonin reuptake inhibitors (SSRIs) like sertraline before considering tricyclics for depression.
Additionally, citalopram, another SSRI, was prescribed to around 1.4 million individuals last year. Patients taking citalopram, on average, lost 0.65 kg and experienced decreases in heart rate and systolic blood pressure, but a slight increase in diastolic blood pressure was noted.
The analysis revealed an approximate weight change difference of 4 kg depending on the prescribed medication. For example, those taking agomelatine lost an average of 2.44 kg, whereas patients on maprotiline, which is not commonly prescribed in the UK, gained an average of 1.82 kg. The heart rate changes were equally striking, with a difference of over 21 beats per minute observed between fluvoxamine, which reduced heart rate by eight beats per minute, and nortriptyline, which increased it by an average of 13.8 beats per minute.
Researchers emphasized the importance of monitoring physical health, as even a 1 kg weight gain can elevate heart risks, and increases in blood pressure may heighten the risk of stroke. However, they recognized that a limitation of the study was its focus solely on the first eight weeks of treatment, warranting further research into longer-term side effects.
Dr. Toby Pillinger, the study”s senior author and consultant psychiatrist at King”s IoPPN, remarked, “Antidepressants are among the most widely used medicines in the world. 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 generally have fewer physical side effects, which may provide reassurance for patients.
Andrea Cipriani, a professor of psychiatry at the University of Oxford, stressed the significance of shared decision-making in treatment, advocating for a collaborative approach that incorporates patients” preferences and circumstances. This philosophy should guide practices within the NHS and beyond.
Commenting on the study, Rosie Weatherly, information content manager at the mental health charity Mind, underscored the necessity for mental health treatments to align with individual patient needs and preferences. She advised individuals concerned about medication side effects to consult their doctors or pharmacists rather than discontinuing treatment without professional guidance.
Professor Azeem Majeed from Imperial College London highlighted the need for regular health checks for patients on antidepressants, emphasizing the importance of being aware of side effects to facilitate informed discussions about treatment risks and benefits. Dr. Lade Smith, president of the Royal College of Psychiatrists, pointed out the critical role of antidepressants in managing severe depression, particularly when combined with talking therapies. He welcomed the study”s contributions to understanding the physical effects of different antidepressants.
Finally, Professor Kamila Hawthorne, chair of the Royal College of GPs, noted that general practitioners prescribe antidepressants judiciously and conduct follow-ups shortly after new prescriptions to monitor for side effects, ensuring that patient reviews remain an integral part of the treatment process.
