Researchers at the University of McMaster in Hamilton have released a study on the health impacts of long-term antidepressant use, arguing that the commonly-prescribed medications raise the risk of death by as much as 33 per cent. The study has already produced a strong reaction from some in the medical community who say that the authors’ interpretation of the results is misleading.
Used by about nine per cent of the Canadian adult population to treat anxiety and depression, antidepressants are now one of the country’s most-prescribed drugs. Statistics show their use in Canada has shot up over the past two decades (but has now apparently levelled off), with Canada now one of the top countries in the world for antidepressant use per capita.
Most-prescribed are the SSRI’s (selective serotonin re-uptake inhibitors) which work by increasing the amount of serotonin, a neurotransmitter known to regulate mood, in the brain. Yet, SSRIs have their effect beyond the brain, argue the new study’s authors, who point out that serotonin is also important for proper functioning of other major organs such as the heart, liver, lungs and kidneys.
To that end, the researchers conducted a review and analysis of past studies involving antidepressant-related mortality, finding 17 studies that met their search criteria. The studies, involving hundreds of thousands of patients, showed that antidepressant use is correlated with a 33 per cent higher risk of death and with a 14 per cent higher risk of cardiovascular events like strokes and heart attacks.
Depression itself comes with negative health correlates, such as increased risk of stroke, heart attack and suicide, which make up part of the reason why physicians prescribe the drugs — the thinking being that, overall, taking them will be more helpful than harmful.
“Our findings are important because they undermine this assumption,” says Mara Maslej of McMaster’s Department of Psychology, Neuroscience and Behaviour and study co-author, in a press release. “I think people would be much less willing to take these drugs if they were aware how little is known about their impact outside of the brain, and that what we do know points to an increased risk of death.”
Yet the findings have been met with criticism from health experts who claim that they overstate the case. Speaking to the Daily Mail, professor David Baldwin, chairman of the Royal College of Psychiatrists in the United Kingdom said, “Depressed patients have higher risks of a range of physical health problems, all of which carry a risk of increased mortality, and antidepressants are often prescribed for a range of problems other than depression, including chronic pain and insomnia, which also increase mortality.”
The study’s authors underline that while their results showed only a statistically insignificant increase in the risk of death for the general population of the study, that included patients with cardiovascular issues (and serotonin works as a blood thinner, thereby making SSRIs a protective measure for those patients). Removing that group from the analysis and controlling for depression resulted in the 33 per cent higher risk for the population without cardiovascular issues.
“The results support the hypothesis that antidepressants are harmful in the general population but less harmful in cardiovascular patients,” say the study’s authors. Their results are published in the journal Psychotherapy and Psychosomatics.