Purpose
Autonomic nervous system (ANS) functioning has long been studied in relation to antisocial behaviour, but relevant measures (heart rate, heart rate variability, pre-ejection period, respiration rate) have rarely been considered together. This study investigated the relationship between these measures and antisocial behaviour.
Methods
Using a sample of 1010 youths with (47.8%) and without conduct disorder (52.2%) aged between 9 and 18years (659 females, 351 males, mean age=14.2years, SD=2.4), principal component analysis (PCA) was applied to various measures of psychopathology and antisocial behavior. Structural equation modelling was performed in order to test whether the ANS measures predicted PCA-dimensions. Cluster analysis was used in order to classify patterns of ANS activity. Analyses were performed separately for males/females and controlled for body-mass-index, age, caffeine use, cigarette smoking, sports, socioeconomic status, medication, cardiac problems.
Results
The PCA yielded three components: antisocial behaviour/comorbid psychopathology, narcissistic traits, and callous-unemotional traits. ANS measures were only weakly correlated with these components. Cluster analysis yielded high and low arousal clusters in both sexes. When controlling for covariates, all associations disappeared.
Conclusion
Our findings suggest that resting ANS measures are only weakly related to antisocial behaviour and indicate that smoking should be considered as an important covariate in future psychophysiological studies.

Reduced responsiveness to emotions is hypothesized to contribute to the development of conduct disorder (CD) in children and adolescents. Accordingly, blunted psychophysiological responses to emotions have been observed in boys with CD, but this has never been tested in girls. Therefore, this study compared psychophysiological responses to sadness in girls and boys with and without CD, and different clinical phenotypes of CD: with versus without limited prosocial emotions (LPE), and with versus without comorbid internalizing disorders (INT). Nine-hundred and 27 girls (427 CD, 500 controls) and 519 boys (266 CD, 253 controls) aged 9–18 years participated. Psychophysiological responses were measured while participants watched two validated sad film clips, specifically: heart rate (HR), respiratory sinus arrhythmia (RSA; indexing parasympathetic activity), preejection period (PEP; indexing sympathetic activity). Girls and boys with CD showed larger HR responses to sadness than controls. This effect was rendered nonsignificant, however, after controlling for covariates. We observed aberrant RSA responses to sadness in CD compared with controls. Similarly, we found a significant positive association between RSA responsivity and antisocial behavior when assessed dimensionally. The effects were very small, though. Results were similar for boys and girls. We found no evidence for emotional underresponsiveness in CD in the largest psychophysiological study to date in this field. More research is needed to explore whether this is specific to sadness or generalizes to other emotions. Furthermore, we recommend that studies on emotion processing in CD assess different physiological measures to help disentangle CD-related effects on sympathetic and parasympathetic activity. (PsycInfo Database Record (c) 2022 APA, all rights reserved)