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Certain Antidepressants Linked to Reduced Risk of Stroke
A new study led by Dr. Christel Renoux, an epidemiologist with the Lady Davis Institute at the Jewish General Hospital, had found that certain selective serotonin reuptake inhibitors (SSRIs) and other antidepressants that increase serotonin levels in the brain the most may be associated with a reduced risk of ischemic stroke when compared to antidepressants that increase serotonin levels the least. The study is published in the August 7, 2019, online issue of Neurology®, the medical journal of the American Academy of Neurology.

SSRIs are the most commonly prescribed antidepressants. An ischemic stroke is when blood flow to part of the brain is blocked. Serotonin is a chemical that transmits signals between nerve cells in the brain. It is released from a cell when sending a signal and then is naturally reabsorbed back into the cells. These drugs inhibit the nerve cells from reabsorbing serotonin, thereby making more of it available in the brain, in the gaps between nerve cells, which improves the brain’s ability to regulate mood.

“It is not uncommon for people with depression to also have heart disease, a risk factor for stroke, so it is important to investigate whether antidepressants raise or lower the risk of stroke,” said Dr. Renoux, an Assistant Professor in the Departments of Neurology and Neurosurgery at McGill University. “While studies investigating stroke risk in people who take antidepressants compared to people who do not take them have found mixed results, our study took an even closer look, investigating stroke risk in people who take antidepressants that increase serotonin levels the most compared to people who take antidepressants that increase levels the least.”

For the study, using a database of more than 15 million people in the United Kingdom, researchers identified over 938,000 adults with an average age of 46 who had been newly prescribed antidepressants, with more than 868,000 taking SSRIs and more than 69,000 taking other antidepressants. Researchers followed study participants for an average of six years. During the study, 15,860 people had a stroke. Those participants were compared to 473,712 participants who did not have a stroke.

The people who used antidepressants that increased serotonin levels the most, had a 12% lower risk of having an ischemic stroke than people who used antidepressants that increased serotonin levels the least. Antidepressants that increased serotonin levels the most included the SSRIs fluoxetine, paroxetine, and sertraline and the drug duloxetine, which is a selective serotonin and norepinephrine reuptake inhibitor (SNRI).

In the analysis assessing the risk of stroke with drugs that increase serotonin levels the most, among 2,836 people with stroke, 2,277, or 80.3 percent, took drugs that increased serotonin levels the most, whereas among 80,821 people who did not have a stroke, 66,577, or 82.4 percent, took drugs that increased serotonin levels the most.

The results remained the same after researchers adjusted for factors that could affect stroke risk, such as obesity, smoking status, alcohol use and high blood pressure.

“The findings of our large study suggest that, compared with the drugs that increase serotonin the least, antidepressants that increase serotonin the most may be associated with a decrease in the risk of ischemic stroke,” said Dr. Renoux. “But given that the decrease in risk is small, we recommend physicians choose antidepressant treatments for their patients based on effectiveness and side effects rather than the risk of stroke.”

A limitation of the study was that the database listed only antidepressants prescribed by general practitioners, not by specialists. However, Dr. Renoux notes that antidepressants are usually prescribed by general practitioners.

The study was supported by Canadian Institutes of Health Research.

For media inquiries and to arrange interviews with Dr. Renoux, contact:

Tod Hoffman
Research Communications Officer
Lady Davis Institute
Tel.: 514-340-8222 x 28661
Email: tod.hoffman@ladydavis.ca

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