Understanding the psychophysiology of Antisocial Behavior in Girls

This thesis aimed to increase the understanding of the mechanisms underlying antisocial behavior in girls. Therefore, we investigated autonomic nervous systsem functioning in a large sample of boys and girls, with and without conduct disorder. First, we assessed baseline ANS activity.,The studies in chapters 2 and 3 suggest that: baseline ANS activity is not related to CD in boys and girls, whereas reduced baseline parasympathetic activity is related specifically to internalizing problems in girls with CD, and increased RR may be a biomarker for CD in girls. Second, we assessed ANS responsivity to different challenges (emotion processing, fear anticipation, psychosocial stress), as decreased ANS responsivity has been previously found the be related to CD. In chapter 4 we observed a decrease in HR during the sad film clips. However, after controlling for covariates, HR deceleration did not differ significantly between girls and boys with and without CD and TDC. As for RSA, we observed an increased response in girls and boys with CD as compared to TDCs, suggesting aberrant parasympathetic responding during emotion processing in CD. However, findings should be interpreted cautiously since we found the aberrant parasympathetic response only during one of the two film clips, and the effect size was small. In chapter 5, we investigated ANS responsivity during fear anticipation. This study suggests a diminished threat sensitivity in CD, and supports the notion that fearlessness is one of the mechanisms underlying antisocial behavior in girls and boys. In Chapter 6 we presented the Trier Social Stress Test (TSST). We found a diminished response in HR and SNS activity, and an increased response in PNS activity in girls and boys with CD as compared to TDCs. Thus, in line with previous studies, we found evidence for blunted autonomic stress-responding in CD, providing further support for fearlessness as the potential mechanism underlying antisocial behavior in youths. Furthermore, this study suggests that impaired responding to psychosocial stress characterizes CD, irrespective of sex, and its clinical phenotype.