Depression, Heart Attack, and Stroke

Feeling low after a frightening medical crisis is common. When someone survives a heart attack or stroke, the weeks of recovery that follow often bring depressive symptoms along with them. Depression itself reaches roughly 350 million people around the world, about 19 million of them in the United States. Clinicians call it major depressive disorder, or clinical depression, when sadness and a sense of hopelessness stop lifting and settle in as a chronic state. The illness can also show up as trouble sleeping, a shifting appetite, fading interest in things that used to matter, aches with no obvious physical cause, and thoughts of suicide.

The relationship runs in both directions. Carrying a depressive disorder raises the odds of a long list of serious, sometimes fatal conditions. Part of why comes down to behavior: depression tends to drain motivation, and a person who stops caring also tends to stop keeping up with the ordinary maintenance of staying healthy. The other part is biochemical. The brain's chemical signaling, its neurotransmission, can go awry in ways that ripple out through the body, producing chronic pain, inflammation, and sluggish circulation. That second pathway is the one that keeps doctors and therapists up at night.

Inflammation and reduced blood flow are a dangerous pairing, and the two conditions they most often set off are heart attack and stroke. Depression left unchecked wears the body down over time and can push it toward cardiac disease, which in turn raises the risk of both events. The lifestyle piece compounds it. People who are depressed smoke more, eat worse, and move less, and those habits feed into high blood pressure, obesity, stress, diabetes, and high cholesterol, each one a step closer to heart trouble.

Because depression turns up so often in cardiac patients, researchers have spent years trying to fight cardiovascular disease by treating the depression behind it. The results have been frustrating. A lot of the studies simply don't carry enough evidence to hand physicians a clear plan of action. Treating depression usually does make life better for the patient, which is something, but researchers have been puzzled that it rarely delivers the cardiovascular payoff they expected. So the question got flipped around: if depression is a risk factor for heart disease, could heading off the depression also head off the heart attack or stroke?

A study run through the School of Science at Indiana University-Purdue University Indianapolis took that angle and found something. The team randomly sorted 235 older patients with clinical depression into two arms. One received collaborative care that treated the depression directly, combining talk therapy with antidepressant medication. The other got standard care with no depression treatment attached. Within the group, 168 participants had no history of cardiovascular problems and 67 did.

The payoff showed up in the patients who started with healthy hearts. Those without preexisting cardiac disease who received the collaborative care were 48% less likely to have a heart attack or stroke across an eight-year window. The standard-care group showed no such benefit. For patients who already had cardiovascular disease going in, treating the depression moved the needle not at all, which was the disappointing half of the finding.

What the numbers argue for is early action: catch and treat depression before it has a chance to fuel something worse. The caveat is that heart disease arrives through plenty of doors that have nothing to do with mood. The researchers lean toward treating the whole person, watching blood pressure, cholesterol, weight, and smoking right alongside the depression rather than picking one and ignoring the rest. Depression carries real weight in how heart disease begins, and preventing it belongs near the top of the list.

Beyond talk therapy, two other depression treatments appear to touch blood flow in the brain, both directly and in roundabout ways: antidepressant drugs and electroconvulsive therapy. Earlier work had already tied low cerebral blood flow to depression, which prompted researchers to ask whether pushing that blood flow back up might ease the illness. Using molecular imaging and nuclear medicine, scientists in the Department of Psychiatry at Hadassah-Hebrew University Medical Center in Jerusalem found that it does: more blood reaching the brain softened the symptoms.

Here is the wrinkle. Most antidepressants nudge cerebral blood flow upward, but electroconvulsive therapy drives it down. So how does the second treatment help anyone? The study's answer is that patients who get little relief from medication tend to respond well to electroconvulsive therapy. Brain imaging confirmed the dip in blood flow during the therapy, yet the same scans showed that as a patient's depression eased, blood flow climbed back up alongside it.

There is more to work out about why different people react so differently to different treatments, but the early signs are encouraging. Matching the right therapy to the right individual can lift the depression by improving blood flow, and that improvement may protect the people most exposed to heart attack and stroke.

Melissa Lavery, M.S.