A recent review indicates that individuals undergoing treatment with specific antidepressants may experience weight changes within the initial two months. While some patients could gain up to 2kg (4.5lbs), others might see a reduction of 2.5kg (5.5lbs) in weight. The study, conducted by researchers from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London, analyzed data from over 150 studies involving 58,534 participants who were administered 30 different antidepressants compared to a placebo.
The research highlighted significant variations in weight fluctuations, heart rate, and blood pressure among the different medications. Notably, the study outcomes, published in The Lancet, aim to inform and empower patients, although it is advised to consult a healthcare professional if any concerns arise.
In England, approximately 92.6 million antidepressants were prescribed to around 8.89 million patients during the 2024/25 period. Sertraline, a commonly prescribed antidepressant, was administered to an estimated 2.9 million patients last year. This medication, also known as Lustral, was associated with an average weight loss of 0.76kg and a decrease in heart rate by two beats per minute, alongside slight elevations in blood pressure levels.
On the contrary, amitriptyline, a tricyclic antidepressant given to 2.2 million patients in England, was linked to an average weight gain of 1.6kg, an increase in heart rate by nine beats per minute, and raised systolic and diastolic blood pressure. It is important to note that tricyclic antidepressants are not the first-line treatment for depression according to the National Institute for Health and Care Excellence, which recommends starting with selective serotonin reuptake inhibitors like sertraline.
Moreover, citalopram, another SSRI prescribed to 1.4 million individuals, was associated with an average weight loss of 0.65kg, along with reductions in heart rate and systolic blood pressure, albeit a slight increase in diastolic blood pressure.
Overall, the study revealed variations in weight changes among different antidepressants, with agomelatine leading to an average weight loss of 2.44kg, while maprotiline, less commonly prescribed in the UK, resulted in an average weight gain of 1.82kg. Heart rate changes also varied significantly, with fluvoxamine decreasing heart rate by eight beats per minute and nortriptyline increasing it by an average of 13.8 beats per minute. The study emphasized the importance of monitoring physical health due to the potential risks associated with weight gain, heart rate fluctuations, and blood pressure increases.
Dr. Toby Pillinger, a senior author of the study and academic clinical lecturer at King’s IoPPN, highlighted the need for informed decision-making and personalized care in antidepressant treatment. Collaborative patient-clinician interactions were also stressed by study author Professor Andrea Cipriani from the University of Oxford, emphasizing the importance of individual preferences and circumstances in treatment decisions.
The study findings were well received by mental health experts, with recommendations for regular physical health assessments for patients on antidepressants. The results underscored the significance of understanding the side effects of different medications to facilitate informed treatment choices tailored to individual needs and preferences.