Abstract
OBJECTIVE: Vagally-mediated heart rate variability (vmHRV) is regarded as transdiagnostic marker of emotion regulation and cognitive control capacity. We analysed vmHRV of children with attention deficit/hyperactivity disorder (ADHD). Based on previous research, we expected to find comorbid symptom dimensions (i.e. internalizing symptoms, conduct problems (CP), and callous unemotional (CU) traits) to relate to vmHRV measures. METHODS: The sample comprised 100 (70 boys) medication naïve children with ADHD. Children were 6 to 11 years old. High frequency HRV (HF-HRV) was measured at rest and during a delay of gratification task. Additionally, sympathetic reactivity was assessed via skin conductance responses (SCR). Comorbid symptoms were assessed by parent-report questionnaires and clinical interviews. RESULTS: The multiple correlation between CU traits and the HF-HRV scores proved statistically significant. Higher CU traits were associated with higher HRV resting-state and response scores. CP were positively associated with the SCR score. CONCLUSION: In children with ADHD, increased CU traits might point to a comparatively less impaired self-regulation capacity in the reward-related context. The result corresponds to findings from previous studies. In the future, CU traits should be considered in analyses of autonomic regulation in ADHD.