Background: Children with ADHD show attentional and cognitive control deficits compared to typically developing controls. However, it is unclear whether these deficits are function-specific to subcomponents of attention and cognitive control and/or disorder-specific, that is, unique to one clinical group.
Methods: Here, we characterized subcomponents of attentional and cognitive control in children with ADHD (N = 37, 21.6% girls), ADHD and comorbid anxiety disorder (AnxD, N = 24, 50% girls), AnxD (N = 39, 30.8% girls), as well as typically developing controls (N = 36, 41.7% girls) aged 7 to 14 years, using behavioral measures from the Attention Network Test (ANT) and AX Continuous Performance Task (AX-CPT). Analysis of variance (ANOVA) and post hoc t-test were used to test for group differences. Cohen's d was used as a measure of effect size for significant group differences.
Results: Children with ADHD and children with ADHD and comorbid AnxD showed lower accuracy (Cohen's d = -0.91/-1.08), higher reaction time variability (Cohen's d = 0.81/1.13) in ANT-derived measures and lower accuracy (Cohen's d = -0.89/-1.04) and A-cue bias (Cohen's d = -0.92/-0.98) in AX-CPT -derived measures compared to controls. Children with ADHD and comorbid AnxD also exhibited higher reaction time (Cohen's d = 0.83) in the ANT and lower d'-context (Cohens' d = -0.97) in the AX-CPT compared to controls.
Conclusion: The results indicate function-specific deficits in cognitive control, but not in attention, among children with ADHD and comorbid AnxD. We did not find strong evidence for disorder-specific deficits in attention or cognitive control.
Keywords: ADHD; anxiety; attention; cognitive control.