Attention-deficit/hyperactivity disorder and task-related heart rate variability: A systematic review and meta-analysis

Research suggests that Attention-Deficit/Hyperactivity Disorder (ADHD) is associated with autonomic nervous system dysregulation, but the findings were mixed. We conducted a literature review and meta-analysis to quantify the effect of ADHD on vagally-mediated heart rate variability (HRV). PsycINFO, PubMed, Web of Science and Scopus, were searched for case-control or cohort studies reporting measures of vagally-mediated HRV, after a task demand, among individuals with ADHD relative to healthy subjects. Thirteen articles comprising a total of 869 patients with ADHD and 909 healthy participants were included. As compared to controls, ADHD patients had reduced vagally-mediated HRV, corresponding to a small effect size (Hedge’s g = 0.20; CI 95% 0.01 to 0.40). Heterogeneity was high (Q (18) = 76.59, p < 0.001; I² = 77%). There was some evidence of small study effects. Task type, respiration rate assessment and associated comorbid disorders were statistically significant moderators. These findings provide evidence for the associations between ADHD and autonomic dysregulation. Future studies addressing HRV reactivity are needed.