Habitual Worry, Cognitive Control, and Heart Rate Variability in Adult ADHD

Adult attention-deficit/hyperactivity disorder (ADHD) is associated with substantial impairments in well-being and quality of life. In addition to cognitive and behavioral symptoms, emotional dysregulation characterizes the disorder. This study investigated habitual worry in the context of cognitive control and heart rate variability (HRV) in adult ADHD. Groups with high and low ADHD symptoms (n = 51 per group) were selected from a large participant pool (n = 1020) using the Adult ADHD Self-Report Scale. HRV was recorded during a breathing focus task assessing cognitive control. The task included two phases during which participants' ability to concentrate on their breathing was recorded before and after an instructed worry phase. While groups did not differ in HRV, participants with high ADHD symptoms reported greater habitual worry, more negative affect, and less positive affect than those with low ADHD symptoms. They exhibited less ability to concentrate on breathing, more frequent positive, neutral, and negative thought intrusions, and greater distress during instructed worry. In the total sample, habitual worry correlated negatively with breathing focus ability and positively with intrusive thoughts. HRV correlated positively with breathing focus ability and negatively with thought intrusions. Moreover, HRV correlated negatively with distress during instructed worry. Impaired cognitive control may contribute to exaggerated worry and negative emotional states related to ADHD symptoms. The lack of association between HRV and ADHD symptoms accords with previous studies. The correlations seen for HRV implicate prefrontal cortex function and vagal cardiac control in emotional regulation and inhibition of intrusive thoughts.