DALLAS, Jan. 20 -- People who are negative, insecure and distressed -- a "type D" personality -- are four times more likely to suffer a second heart attack than "non-D types," according to a study reported today in Circulation: Journal of the American Heart Association.
The findings are the first to suggest that a personality trait may influence the risk of a repeat heart attack, says lead author Johan Denollet, Ph.D., of the University of Antwerp, in Edegem, Belgium.
In the study, psychological tests were given to 87 men who had a severe heart attack. The men were at high risk for second heart attacks because of a decreased left ventricular function, resulting in a less effective pumping of blood.
Six to 10 years later researchers determined that the rate of recurrent heart attack for "type D" personality types was 52 percent compared to 12 percent for "non-type D" individuals.
Previous investigations have found associations between increased heart attack risk and psychological characteristics such as anxiety and depression. But the Belgium team suspected that personality might be a third psychological factor influencing a person's risk.
"Type D" personality types were identified based on their scores of negative affectivity -- having ongoing feelings of worry and anxiety -- and social inhibition, or being insecure and lacking assertiveness.
Individuals who scored above average on negative affectivity and social inhibition were considered "type D."
In other research, "type A" behavior -- characterized by anger and hostility -- also has been implicated as a risk factor for heart attack, although "research has produced inconsistent findings," says Denollet. A second behavior type, called "type B," is the opposite of "type A" and is characterized by lower level of energy and arousal.
Denollet says the "type D" personality provides a "more accurate" approach to understanding psychological influences on heart disease because it looks at two personality traits, rather than a "hodgepodge" of signs and symptoms associated with the behavioral type "A" and "B" or mood states such as depression or anxiety.
Much like high blood pressure or elevated cholesterol, the "D" personality may help identify individuals at risk, says Denollet.
In an editorial accompanying the study, Robert M. Carney, Ph.D., comments that the study is important because it advances the understanding of psychological factors that may increase the risk of heart attack.
"Their study is the first to show that after a heart attack, the risk of having another cardiac event is higher in people who are both socially inhibited and psychologically distressed, compared to patients with only one of these problems or to those with neither problem," says Carney, a professor of medical psychology at Washington University School of Medicine in St. Louis, Missouri.
However, he cautions that personality traits such as "type D" tend to be much harder to change than other psychological risk factors such as depression, anger, or anxiety.
Thus, he says, we should continue to concentrate on helping patients overcome depression and other negative moods, as well as help shy or socially inhibited patients to improve their social life, instead of trying to change their personality.
"Even if it were easier for health care providers to screen their patients for a single personality trait than for several different negative mood states, this advantage would be outweighed by the difficulty of changing their patients' personalities," says Carney.
"It would be a mistake to abandon research on depression, anxiety, anger, and social support in favor of the "type D" personality trait," he says.