Post-traumatic stress disorder (PTSD) is an anxiety disorder that is triggered by memories of a traumatic event. Building on research from the late 1990s, researchers at the Harvard School of Public Health have discovered a new aspect of PTSD: it may increase the risk of heart disease.
Triggering Traumatic Memories
PTSD can occur following the trauma of military combat, as well as natural disasters, terrorist attacks, and physical or sexual abuse. The disorder’s many symptoms may include flashbacks, emotional deadening, arousal symptoms such as anger and difficulty sleeping, and physiological reactions such as increased blood pressure, rapid heartbeat and breathing, and muscle tension. These symptoms typically appear within three months of the event, but in some cases they take years to surface.
In the brain, PTSD affects the amygdala and hippocampus, which regulate components of cognition. The amygdala, an almond-shaped structure located deep within the brain, governs the expression of emotions and the detection of potentially threatening stimuli. The hippocampus encodes emotional events and provides context for responses to fear. During these events, the amygdala and hippocampus communicate with each other.
PTSD Symptoms Increase Risk
The Harvard study, published in the January Archives of General Psychiatry, examined data from the Veterans Administration Normative Aging Study, a long-term research project that tracks the health of military veterans in the Boston area. Laura Kubzansky, who studies psychological factors that may be involved in the etiology of heart disease, and her colleagues analyzed the responses of male World War II and Korean War veterans to questionnaires measuring PTSD symptoms. Topics included sleep difficulties, nightmares, and disturbing memories of traumatic events.
One questionnaire was administered in 1986, the other in 1990. Some of the veterans answered only one questionnaire, although many responded to both. On average, the men were in their 60s when they answered either questionnaire.
In the years since completing the surveys, the veterans with stronger PTSD symptoms suffered higher rates of coronary heart disease, suggesting that “prolonged stress and significant levels of PTSD symptoms may increase the risk of coronary heart disease in older male veterans,” Kubzansky writes.
She suggests two explanations for this increased risk. First, people with PTSD often engage in behaviors that can cause heart disease, including smoking, physical inactivity, and alcohol abuse.
Kubzansky notes, however, that many of these behaviors were accounted for in her study, and the researchers still found an effect. This suggests a second possibility: that PTSD is associated with increased physiological reactions that flood the body with hormones and neurochemicals in response to stress.
“While these [stress reactions] help the body meet short-term threats, over time, when the body gets no rest or break from this activation, it can cause wear and tear on the heart,” she says.
Link Suggests a “Trend”
In 1999, Joseph Boscarino, then with Catholic Health Initiatives, reported a higher rate of heart problems, including heart attacks, among combat veterans of the Vietnam War who were suffering from PTSD at the time of the study compared with noncombat veterans. Boscarino, now at Geisinger Health System, is studying Vietnam veterans, looking into the relationship among stress hormones, psychiatric disorders such as PTSD, and inflammatory cardiovascular disease.
Boscarino says physiological and biological measures of stress reaction revealed higher responses among people with PTSD who were responding to startle-response stimuli. These include increases in stress hormones and a decrease in cortisol, which regulates inflammation. Decreased amounts could contribute to atherosclerosis.
“We tend to see a relationship between PTSD and heart disease over and over in different studies,” Boscarino says. “There’s a trend.”
Another study, published in the American Journal of Psychiatry in January, revealed that Iraq combat veterans with PTSD reported worse physical health, more visits to the doctor, and more missed workdays than combat veterans without PTSD. The study, led by the Walter Reed Army Institute of Research, did not specifically look at heart disease, but the Army researchers say it affirms the significant mental health burden combat veterans face.
Kubzansky says the next step is to conduct studies to determine the mechanisms linking PTSD and heart disease.