Antidepressant Use Linked With Increased Atherosclerosis

Antidepressants and carotid IMT

April 02, 2011

April 2, 2011 (New Orleans, LA) -- Antidepressant medications might be associated with an increased burden of atherosclerosis as measured by carotid intima-media thickness (IMT), according to new observational data presented today at the American College of Cardiology 2011 Scientific Sessions . The study looked at a large cohort of male twins, enabling researchers to look at antidepressant usage as a whole, but also between brothers where one twin was taking an antidepressant, and the other wasn't.

"What we found was that the twins who were taking the antidepressants had thicker carotid IMT than the twins who were not taking the antidepressants," said lead investigator Dr Amit Shah (Emory University School of Medicine, Atlanta, GA). "The size of the effect was about a 5% increase in the carotid IMT, or more quantitatively, a 40-μm increase. Now, to put that into more lay terms, each year that a person lives, naturally their carotid IMT increases by about 10 μm, so the brother who was taking the antidepressants had neck vessels that were four years older than the brother who was not taking the antidepressants in our study."

Speaking during an afternoon press conference announcing the results, Shah said that various neuropeptides, including serotonin, the target of antidepressant drugs such as selective serotonin-reuptake inhibitors (SSRIs), can cause vasoconstriction of various blood vessels. Although antidepressants might augment the release of these vasoconstrictive neuropeptides, the data analyzing the effects of the antidepressant medications on cardiovascular risks are conflicting, and few studies have assessed the vascular effects of the drugs. One past study, an analysis of the Women's Health Initiative, suggested that SSRIs were linked to an increased risk of hemorrhagic and fatal stroke, he noted.

In this analysis of 513 middle-aged male twins participating in the Vietnam Era Twin Registry, the investigators measured carotid IMT using ultrasound and also assessed traditional ischemic heart-disease risk factors. Depression and posttraumatic stress disorder (PTSD) were measured using structured clinical interviews for the diagnosis of psychiatric disorders, and depressive symptoms were measured with the Beck Depression Inventory.

In total, 16% of patients were taking antidepressants, and of these, 60% were taking SSRIs. After researchers controlled for ischemic heart-disease risk factors, depression, PTSD, and alcohol and coffee intake, antidepressant use was associated with an adjusted increase in carotid IMT (β=3.7 μm; p=0.006). In a within-pair analysis of brothers discordant for antidepressant use, the adjusted association between antidepressant use and increase in carotid IMT remained (β=4.1 μm; p=0.01). This within-pair association was similar for individuals taking SSRIs and those taking other drugs. Investigators did observe a significant interaction between antidepressant use and depressive symptoms.

"We found that twins who were experiencing more depressive symptoms at the time we measured the thickness of their blood-vessel walls showed more of an association between antidepressants and carotid IMT," said Shah. "If you look at all twins taking antidepressants and the increase in thickness, the ones who had the most increase in thickness were the most depressed."

To heartwire , Shah said that increased atherosclerotic burden of the carotid artery is not on the radar of practicing clinicians, including psychiatrists, and that most are instead concerned with sleep, appetite, and sexual side effects as well as weight gain. While these data should not be used to take patients off medications, the clinician needs to assess the benefits and risks on a patient-by-patient basis.

"It's important to take studies like this into account when assessing risks and benefits, particularly in cases where patients might not be experiencing much benefit from antidepressants," said Shah. He stressed, however, the observational nature of the analysis, noting that these results do not imply causality. He added that antidepressants provide symptom relief of depression and that depression itself is a risk factor for heart disease.

The authors report no conflicts of interest.

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