| Biological (e.g. physiological, endocrinological) and psychosocial factors (e.g. personality, stressful life events) both contribute to the etiology of psychopathology. Recent years have witnessed increased interest in physiological correlates of psychosocial functioning and its links to externalizing and internalizing psychopathology in children and adults. Different levels of activity of the two branches of the autonomic nervous system (ANS), the sympathetic (SNS) and the parasympathetic nervous system (PNS), are supposed to be reflected in differences in behavioral reactivity, motivation, and regulation. Hyperactivity of the SNS (overarousal, increased reactivity) appeared to be mainly involved in stress-related health problems (e.g. depression, anxiety disorders) through increased cardiovascular stress reactivity, whereas SNS hypoactivity (underarousal, decreased reactivity) has been mainly linked to externalizing disorders (e.g. conduct disorder, antisocial behavior). Moreover, vagal activity of the PNS is supposed to be a physiological index for behavioral control, inhibition, and flexibility. It has been proposed that individuals with greater vagal tone would exhibit a greater range of competent behaviors. Conversely, reduced vagal tone would be paralleled by reduced behavioral flexibility in response to environmental demands. Reduced vagal activity has been reported in both internalizing and externalizing psychopathology. It has been suggested that divergent patterns of ANS functioning may be related to core dimensions of temperament (inhibiton and approach) and psychopathology (internalizing and externalizing). However, previous research has reported mixed results. The association between different indices of the ANS and psychosocial functioning seems to be complex and is not yet fully understood. In addition, most research has focused either on one branch of the ANS or one single type of personality construct or psychopathological dimension. Also, knowledge about ANS function and psychosocial factors in children is limited as is literature on the physiological correlates of temperament. The present study is embedded in two longitudinal epidemiological studies, TRAILS (child cohort) and SALUT (adult cohort). Data collected in the first wave of about 1800 preadolescents and 1500 adults will be analyzed in a cross-sectional design. To summarize, the aim of the present study is to investigate the relationship between ANS function and psychosocial variables, that is personality, stress, and psychopathology. The main goal of this study is to increase insight into the etiology of different kinds of psychopathology, focusing on the possible role of the autonomous nervous system. In addition, early detection of autonomic abnormalities may greatly enhance the prevention of future health problems. |