Antidepressants taken by millions of Britons could increase the risk of sudden cardiac death up to five-fold, a study suggests.
Experts in Denmark discovered that patients who took these medications for one to five years faced a 50 percent higher risk of dying from a sudden heart problem.
Taking the mood-boosting drugs for six years or more was found to increase the risk by just over 100 per cent.
The research comes at a time when statistics indicate that approximately 8.7 million individuals in England are currently using antidepressants, accounting for about one in seven people, and this number continues to rise annually.
Prominent psychiatrists from around the world expressed to MailOnline their shock at the results, emphasizing the dangers of widely prescribing these potent medications to millions of people and stressing the importance of providing patients with adequate warnings.
But other experts have urged caution over the study, with patients urged not to quit taking their medication without talking to the medical professional responsible for their care first.
In the study, a sudden cardiac death was defined as the unexpected fatality of a person from a heart related issue, between one and 24 hours of onset of symptoms.
Danish experts, who analysed all deaths recorded in the country in 2010, found 6,002 cases of sudden cardiac death, one third of which were among patients taking antidepressants.
Health service figures show a record 8.7 million people in England, about 15 per cent of the total population, are now on the mood-boosting drugs
Overall, the researchers found individuals prescribed antidepressants had a far higher chance of dying this way compared to non-users, with the risk increasing the longer the patients took the drugs.
However, the increased risk was higher in certain age groups.
The highest increased risk was seen among 30-to-39-year-olds, who had triple the risk of sudden cardiac death if they took antidepressants for one to five years, and a five-fold increased risk if they took them for six years or more.
Study co-author, Dr Jasmin Mujkanovic, said exactly why these patients were at increased risk of dying remained unclear.
‘The increased risk of sudden cardiac death may be attributed to the potential adverse effects of the antidepressants,’ she said.
‘However, the exposure time to antidepressants might also serve as a marker for more severe underlying illness.
‘Additionally, the increase could be influenced by behavioural or lifestyle factors associated with depression, such as delayed healthcare seeking, and poor cardiovascular health. Further research is warranted.’
World-renowned University College London psychiatrist Professor Joanna Moncrieff told MailOnline that medics had known antidepressants were ‘cardiotoxic’, meaning they damage the heart, for years.
However, she added the new study was the strongest evidence yet that this was leading to deaths.
‘It’s another shocking example of an adverse effect that’s taken too long to come out even though we had good reason to suspect that these drugs are cardiotoxic,’ she said.
‘We know they affect the heart, they change the way the heart beats, the heart’s rhythm.
‘It’s an adverse effect that doctors and patients haven’t been aware of enough in the past, so people need to be warned about it.’
Professor Moncrieff highlighted that while the overall risk of sudden cardiac death was low in the study, about one per 1,000 each year, the scale at which medics were dishing out antidepressants meant thousands of patients could be at risk.
‘The risk of sudden cardiac death is low, it’s not a common phenomena, so even with those increased risks, it’s still not going to be common,’ she said.
‘But there are so many people on these drugs that even if sudden cardiac death is rare, that’s still going to be a significant number of people who are affected.’
Other experts have urged caution of the study’s findings, arguing that the increased risk of sudden cardiac death could be due to the depression the drugs are designed to treat rather than the medication.
This NHS data shows the number of Brits taking each type of antidepressant medication over the past eight years. The line with the green triangles indicates the the total number of patients
Dr Paul Keedwell, psychiatrist and fellow of the Royal College of Psychiatrists, said: ‘Depression is associated with high levels of heart disease, including sudden cardiac death, 60 per cent higher than non-depressed, life-threatening abnormal heart rhythm, 50-90 per cent increase in risk, and heart attack, roughly double the risk.’
He added that patients with depression also tended to be in poorer physical health in general, a factor that could increase their risk of serious heart problems.
‘Depressed individuals have an unhealthy lifestyle – they are more inactive and lack the motivation to cook healthy meals because of their illness,’ he added.
Dr Keedwell also highlighted that even if the risk of cardiac deaths from the drugs was real, the risk of suicide among these patients would still be greater, meaning the drugs would still be recommended.
‘Sudden cardiac death is a relatively rare event in the total population of depressed people, especially below 40, while the absolute risk of early death from suicide and other physical health problems is likely to be much higher,’ he said.
‘More research is needed to directly compare the life expectancy in treated and untreated depression, but, as things stand, the weight of evidence supports the conclusion that the risk of early death is much higher when depression is left untreated than when it is treated.’
Professor Moncrieff also added there were unanswered questions on the link between cardiac health risks and antidepressants that needed further research.
This included unpicking how much of this increased risk could be linked to the drugs themselves or depression as a condition, as well as whether different types of antidepressants carried different levels of risk.
Uptake of antidepressants has soared in recent years, despite growing unease among experts about the effectiveness of the drugs in treating depression.
However, plenty of patients taking them insist they work.
NHS figures show a record 8.7million people in England, about 15 per cent of the total population, are now on the mood-boosting drugs.
Previous studies have linked their use to health issues including heart problems in young people alongside long-term and even permanent sexual dysfunction.
Psychiatrists advise patients concerned about the side effects of antidepressants to talk to their medical professional about their options.
Clinicians can sometimes offer an alternative dose, a different drug, or prescribe another medication to combat the side effects.
They urge patients who are taking them not to quit without talking to the medical professional responsible for their care first to ensure they are adequately supported.
The Danish study was presented at the annual congress of the European Heart Rhythm Association in Vienna, Austria.
