NEW ANTI-DEPRESSANT WARNING.
Analysis doesn’t prove cause and effect, critics say
Psychiatrists 50 years from today may look back and ask did the drugs they used to treat brains harm the body?
Controversial new research suggests antidepressants dispensed by the millions in Canada increase the risk of dying early.
Prominent psychiatrists not involved in the work called the paper premature and alarmist, arguing antidepressants can be “life savers.”
But the study’s lead author suspects the ubiquitous pills take more lives than they save and that one way they might take lives is through their effect on platelets, tiny cells in the bloodstream that form clots to stop bleeding.
Platelets need the brain chemical serotonin to function properly. The most popular antidepressants on the market block the absorption of serotonin.
The result, the researchers speculate, is the drugs effectively act like blood thinners, increasing the risk of abnormal bleeding and hemorrhagic stroke.
In fact, all commonly prescribed antidepressants target one or more of these “monoamines” — molecules that have broad effects beyond the brain, the researchers write in the journal Psychotherapy and Psychosomatics.
By interfering with the function of platelets, “It’s possible for a normal person to have increased risk of stroke or upper GI (gastrointestinal) bleeding or other sorts of abnormal bleeding events that could be harmful or deadly,” said the study’s lead author Paul Andrews, an evolutionary biologist and associate professor at Hamilton’s McMaster University.
The drugs appeared less risky in people already with heart disease, perhaps by keeping blood flowing through constricted or narrowed arteries.
Canadians are among the top antidepressant users in the world. More than 50 million prescriptions were filled in 2015 alone, according to market research firm IMS Brogan.
But there is growing evidence the drugs offer little advantage over placebo for mild depression and psychiatrists have been accused by some of their own of being overly liberal with the use of the mood-altering pills. However, family doctors, who are ordering antidepressants for an ever-growing litany of ills, including insomnia, hot flashes and chronic pain, are doing the bulk of the prescribing.
For their study, the researchers conducted a metaanalysis, reviewing 16 studies involving more than 378,000 people. They found antidepressant (AD) users had a 33 per cent higher chance of death over people not on the drugs. They also had a 14 per cent higher risk of having a “new” cardiovascular event such as stoke or heart attack.
Depression itself is associated with an increased risk of death, including suicide. But Andrews said in order to meet the team’s search criteria the studies had to control, in one way or another, for the mortality of depression.
In the brain, serotonin acts as a neurotransmitter. However, most of the body’s serotonin is synthesized in the gut. From there it spills out into the bloodstream and is taken up by cells, tissues and organs throughout the body, Andrews said.
Serotonin also appears to be important for mitochondria, which act like miniature power plants, supplying energy to virtually every cell in the body.
Among other side-effects, selective serotonin reuptake inhibitors (SSRIs) have been known to cause abnormally slow heartbeats and fainting. Another Canadian study published earlier this year linked the pills to a twofold increase in the odds of developing dementia.
Dr. Joel Paris, past chair of psychiatry at Montreal’s McGill University, said the analysis doesn’t prove cause and effect. Among other weaknesses, he said the study also didn’t adjust for duration or dose.
“A single study like this shouldn’t frighten anybody,” he said. “You’ve heard about the replication crisis in medicine and psychology?
“More people are taking (antidepressants) for a lifetime. So is this safe? Up to now we have said we haven’t seen any problems.”
Dr. David Baldwin, chair of the psychopharmacology committee of the Royal College of Psychiatrists in the U.K., told the Daily Mail people with depression are at higher risk of a range of health problems to begin with, “all of which carry a risk of increased mortality.”
A spokesman for the college added anti-depressants “are a life saver for many, reducing the risk of suicide in depressed patients.”