Heritability of anxiety sensitivity: A twin study

Objective: In attempting to explain the familial predisposition to panic di sorder, most studies have focused on the heritability of physiologic charac teristics (e.g., CO2 sensitivity). A heretofore unexplored possibility is t hat a psychological characteristic that predisposes to panic-anxiety sensit ivity-might be inherited. In this study, the authors examined the heritabil ity of anxiety sensitivity through use of a twin group. Method: Scores on t he Anxiety Sensitivity Index were examined in a group of 179 monozygotic an d 158 dizygotic twin pairs. Biometrical model fitting was conducted through use of standard statistical methods. Results: Broad heritability estimate of the Anxiety Sensitivity Index as a unifactorial construct was 45%. Addit ive genetic effects and unique environmental effects emerged as the primary influences on anxiety sensitivity. There was no evidence of genetic discon tinuity between normal and extreme scores on the Anxiety Sensitivity Index. Conclusions: This study suggests that one psychological risk factor for th e development of panic disorder-anxiety sensitivity-may have a heritable co mponent. As such, anxiety sensitivity should be considered in future resear ch on the heritability of panic disorder.