Cardiac vagal tone is an indicator of parasympathetic nervous system functioning, and there is increasing interest in its relation to antisocial behavior. It is unclear however whether antisocial individuals are characterized by increased or decreased vagal tone, and whether increased vagal tone is the source of the low heart rate frequently reported in antisocial populations.

Participants consisted of four groups of community-dwelling adolescent boys aged 15.7 years: (1) controls, (2) childhood-only antisocial, (3) adolescent-only antisocial, and (4) persistently antisocial. Heart rate and vagal tone were assessed in three different conditions: rest, cognitive stressor, and social stressor.

All three antisocial groups had both lower resting heart rates and increased vagal tone compared to the low antisocial controls across all three conditions. Low heart rate partially mediated the relationship between vagal tone and antisocial behavior.

Results indicate that increased vagal tone and reduced heart rate are relatively broad risk factors for different developmental forms of antisocial behavior. Findings are the first to implicate vagal tone as an explanatory factor in understanding heart rate – antisocial behavior relationships. Future experimental work using non-invasive vagus nerve stimulation or heart rate variability biofeedback is needed to more systematically evaluate this conclusion.

Leading theories suggest that borderline personality disorder (BPD) is an emotion dysregulation disorder involving lower basal vagal tone, higher baseline emotion, heightened emotional reactivity, delayed emotional recovery, and emotion regulation deficits. However, the literature to date lacks a unifying paradigm that tests all of the main emotion dysregulation components and comprehensively examines whether BPD is an emotion dysregulation disorder and, if so, in what ways. This study addresses the empirical gaps with a unified paradigm that assessed whether BPD is characterized by five leading emotion dysregulation components compared to generalized anxiety disorder (GAD) and healthy control (HC) groups.

Emotion was assessed across self-report, sympathetic, and parasympathetic indices. Participants with BPD, GAD, and HCs (N = 120) first underwent baseline periods assessing basal vagal tone and baseline emotional intensity, followed by rejection-themed stressors assessing emotional reactivity. Participants then either reacted normally to assess emotional recovery or attempted to decrease emotion using mindfulness or distraction to assess emotion regulation implementation deficits.

Individuals with BPD and GAD exhibited higher self-reported and sympathetic baseline emotion compared to HCs. The BPD group also exhibited self-reported emotion regulation deficits using distraction only compared to the GAD group.

There is minimal support for several emotion dysregulation components in BPD, and some components that are present appear to be pervasive across high emotion dysregulation groups rather than specific to BPD. However, BPD may be characterized by problems disengaging from emotion using distraction.