“Studies have shown that biological changes take place within the body when depression is present, and patients are not as adherent to medications, prescribed behavioral regimens. They also make more poor choices,” May said.
Lana Watkins is an associate professor in psychiatry and behavioral sciences at Duke University in Durham, N.C. Because the study didn’t randomly assign patients to different groups, she said there’s no definitive message from the findings.
“More treatment studies are needed in order to determine whether it is depression itself that is responsible for the increased risk,” said Watkins, who wasn’t involved in the research.
It’s possible, she added, that something else affected death rates, perhaps disease severity or the fact that people with depression may be more likely to have multiple illnesses.
May acknowledged that the study has a major limitation: It didn’t analyze whether depression treatment affected length of survival, so it’s not known how beneficial better screening and timely depression treatment might be. Future research should examine that issue, she said.
Watkins noted that one prior study suggested that successfully treating depression failed to reduce death risk in patients after a heart attack. “The relationship between depression and risk [of dying] may be more complicated than originally thought,” she said.
Regardless, another mental health expert said depression treatment would benefit these people overall. Even if it doesn’t prolong survival, “there is good evidence that it will improve quality of life,” said Robert Carney, director of the Behavioral Medicine Center at Washington University School of Medicine in St. Louis.
After screening for depression, “if symptoms persist more than a few weeks, providing counseling or, if appropriate, psychotherapy or antidepressants for patients with clinically significant depression should be considered,” said Carney, who is also a professor of psychiatry. He wasn’t involved in the study.
The study results will be presented March 17 at the American College of Cardiology’s annual meeting, in Washington, D.C. Research released at conferences should be considered preliminary until published in peer-reviewed medical journals.