Response inhibition and emotional responding in attention-deficit/hyperactivity disorder with comorbid disruptive, impulse-control, and conduct disorders

Abstract

To characterize the traits of neuropsychological functioning deficits in patients with attention-deficit/ hyperactivity disorder (ADHD) with comorbid disruptive, impulse-control, and conduct disorders (DICCD). Twenty out-patients with ADHD, 20 with ADHD with comorbid DICCD, and 20 with DICCD, all aged 6-16 years, were enrolled in this study, with 20 healthy subjects matched for age, gender and IQ serving as the healthy controls. The patients were diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Revision (DSM-5). All the subjects were assessed with Golden Stroop test and emotional Stroop test to evaluate their response inhibition and emotional responding. In Golden Stroop test, the interference scores (IGs) of errors and reaction time both differed significantly among the groups (P < 0.05), and were the highest in patients with ADHD only. In emotional Stroop test, the mean reaction time (MRT) showed significant differences among the groups (P < 0.05); the MRT of positive- congruent trials in ADHD with comorbid DICCD group was shorter than that in ADHD group but longer than that in group DICCD; the MRT in the 3 case groups were all longer than that in the control group. The MRT of both positive-incongruent trials and negative-congruent trials in ADHD with comorbid DICCD group and DICCD group was shorter than that in ADHD group but longer than that in the control group. The MRT of negative- incongruent trials in DICCD group was shorter than that in ADHD group and ADHD with comorbid DICCD group but longer than that in the control group. The response inhibition deficit and abnormal emotional responding are the core symptoms of ADHD. Bias emotional stimuli may render response inhibitory dysfunction in patients with DICCD with callous-unemotional traits of emotional responding disorder, especially in dealing with negative emotional trials, while the comorbidity of ADHD and DICCD tends to have the emotional response trait of DICCD.