Nearly nine million people in England, approximately one in six of the population, were prescribed antidepressants in the past year. While these medications are widely recognized for their effectiveness in treating depression and anxiety by increasing serotonin levels, concerns are mounting regarding the long-term effects of their use.
Official figures indicate that about half of those on antidepressants have taken them for over two years, with a quarter using them for more than five years. Although long-term use is considered by some to be vital in preventing relapse and suicide for individuals with severe depression, and also used for conditions like PTSD and chronic pain, experts are questioning whether the benefits of extended use are being overstated.
Emerging research suggests potential links between prolonged antidepressant use and serious side effects, including heart problems, weight gain, bone weakening, fractures, sexual dysfunction, type 2 diabetes, and cognitive decline. However, a definitive causal link has not been established for all these conditions.
Professor Joanna Moncrieff, a psychiatrist at University College London, has been involved in a study reviewing research on the side effects of long-term antidepressant use, focusing on individuals taking the medication for over a year. The study, which is yet to be published, found associations with type 2 diabetes, weight gain, and an increased risk of falls and fractures in older adults. "We certainly can't say that long-term antidepressants are safe or harmless," Professor Moncrieff stated, adding that the evidence for their long-term effects is limited and often of low quality, suggesting the issue has not been adequately investigated.
Psychiatrist Dr. Sameer Jauhar from Imperial College London highlighted that different antidepressants may have distinct long-term effects, particularly on the heart, which should be considered in prescribing decisions. Current guidance from the National Institute for Health and Care Excellence (NICE) suggests that individuals consider stopping antidepressants after at least six months of significant improvement, though longer use is permitted for recurring depression.
Distinguishing between side effects caused by antidepressants and those stemming from depression itself is challenging. Depression is a known risk factor for various chronic diseases, and lifestyle factors associated with the illness can also contribute to health problems. Many studies identifying links are observational, showing associations rather than proving causation.
However, some experts believe the biological mechanisms are plausible. Dr. David Healy, a psychiatrist who has researched antidepressant side effects, points out that serotonin receptors are present throughout the body, not just in the brain, suggesting that increasing serotonin levels could impact various bodily functions over time. He draws a parallel with antibiotics, which are effective short-term but can pose problems with prolonged use.
Well-established immediate side effects include emotional blunting, sleep disturbances, gastrointestinal issues, and weight gain. Selective serotonin reuptake inhibitors (SSRIs), the most common type, can also lead to sexual dysfunction. Older antidepressant classes, such as serotonin-norepinephrine reuptake inhibitors (SNRIs) and tricyclic drugs, can affect heart rate, blood pressure, and cholesterol levels by increasing the 'fight or flight' hormone noradrenaline.
Of particular concern is the potential for some antidepressants to prolong the QT interval on an electrocardiogram. A prolonged QT interval can disrupt the heart's rhythm, potentially leading to palpitations, dizziness, and, in rare instances, sudden cardiac death. A 2025 study presented to the European Society of Cardiology found a 56% increased risk of sudden cardiac death associated with antidepressant use between one and five years, with longer use correlating with greater risk.
Professor Moncrieff noted that while these effects are plausible given the drugs' known impact on cardiac electrical activity, other factors might also influence study outcomes. The link with type 2 diabetes appears stronger, with weight gain contributing, but researchers also suspect the drugs may affect the body's blood sugar regulation.
Evidence also points to an increased risk of fractures, particularly in individuals over 50 taking SSRIs or tricyclic antidepressants. A 2010 warning from the UK's Medicines and Healthcare products Regulatory Agency (MHRA) suggested this risk could double and increase with longer duration of use, though the exact reasons are unclear, with lifestyle factors also playing a role.
The connection to dementia is less certain, as depression is a significant risk factor. However, some older antidepressants may affect memory, and a 2025 Swedish study suggested that high doses of SSRIs could accelerate cognitive decline in individuals with existing dementia.
Another concern with long-term use is the potential for more severe withdrawal symptoms, including anxiety, low mood, and insomnia. Experts emphasize that patients should consult healthcare professionals before discontinuing or altering their medication.
Dr. Alison Cave, MHRA chief safety officer, stated that all antidepressants have unique benefits and risks, which are detailed in patient information leaflets. She stressed the importance of patients continuing their medication and consulting with doctors or pharmacists if they have concerns about side effects.
Rachel Buckmaster, a scientist who experienced heart palpitations after five years on the antidepressant citalopram for PTSD, shared her experience. Although doctors did not directly attribute her palpitations to the medication, they advised her to stop taking it. Her palpitations ceased after she discontinued the drug, though it took three months for her mood to stabilize. She expressed that she was never warned about such potential risks associated with long-term use.