Personality traits and psychophysiological reactions to a stressful interview in twins with varying degrees of coronary heart disease.

A series of male twin pairs aged 51–74 (mean 62), the majority of whom were discordant with regard to coronary heart disease (CHD), 17 monozygotic and 13 dizygotic pairs, were subjected to psychologic and psychophysiologic evaluation. None of a number of CHD-related psychologic measures differentiated significantly the “more healthy” from the “less healthy” partners. Two measures of Type A behavior as well as “muscular tension” and “impulsivitiy” showed evidence of genetic influence. A likely genetic influence was also demonstrated over peripheral vasoconstriction, blood pressure (systolic and diastolic) as well as plasma growth hormone level during and after a stressful interview but not during rest. Heart rate was demonstrated to be under genetic influence both at rest and during interview.