Introduction. Adverse Childhood Experiences (ACEs) are associated with psychopathy. However, the physiological mechanisms underlying this association are unclear. This study examines whether sympathetic and parasympathetic nervous system (PNS) processes may explain the link between ACEs and psychopathy. 

Methods. Antisocial behavior was assessed in 335 boys from ages 7-17 years. Nineteen ACE measures were collected from self-reports, teacher-reports, and parent-reports throughout different phases of the 10-year study and averaged into one overall ACE measure. At age 16-17, vagal tone and heart rate were measured during a resting state, a social challenge, and a cognitive challenge along with parent-report and child-report psychopathy.  

Results. ACEs were positively associated with higher parent-reported psychopathy (r= .193, p < .001). Parent-reported psychopathy was positively associated with increased vagal tone during the cognitive stressor (r = .194, p < .001) and rest (r = .126, p=.028), but not the social stressor (r = .088, p=.129). Mediation analyses indicated that increased vagal tone during the cognitive challenge, but not heart rate, partially mediated the relationship between ACEs and parent-reported psychopathy(p=.024). 

Discussion. Findings are to our knowledge the first to document the mediating role of parasympathetic activity on the relationship between ACEs and psychopathy. Results challenge the perspective that antisocial behavior is consistently associated with decreased vagal tone and suggest instead that ACEs may predispose an individual to heightened vagal tone in cognitively stressful situations. Neurodevelopmentally, ACEs may wire the PNS for increased vagal tone and low heart rate. Overall, findings support a parasympathetic dominance theory of psychopathy.