background Neuroticism is widely used as a marker of vulnerability for psychopathology. However, neuroticism is of little value as an explanatory concept in research into the etiology of psychopathology.
aim To study the genetic association between neuroticism and cardiovascular autonomic nervous system (ans) measures in order to increase the explanatory value of neuroticism.
method Electrocardiograms and finger blood pressure for 125 female pairs of twins were assessed during four experimental conditions. Mean values for baroreflex sensitivity (brs), heart rate variability (hrv) and inter-beat-interval (ibi) were calculated. Neuroticism was assessed by means of several questionnaires. Multivariate genetic modelfitting analyses were used to investigate the genetic correlation between latent neuroticism and the ans measurements.
results Neuroticism was negatively correlated to brs and hrv (r=-0.26, p=0.003; r=-0.26, p=0.002, respectively). Neuroticism was not significantly related to ibi (r=-0.13, p=0.11). For brs, this phenotypical relation was entirely determined by shared genetic influences. For hrv, the proportions of explained covariance showed a trend of more genetic than environmental influences on the phenotypical relationship.
conclusion Severe neuroticism is associated with a deregulated ans. Pleiotropic genetic effects may be partly responsible for this effect. The genetic association between neuroticism and the function of the hypothalamic-pituitaryadrenal axis function is currently under study and will also be discussed.