[Characteristics of executive function in children with attention deficit/hyperactivity disorder comorbid with high...

Objective: To explore the characteristics of executive function in children with attention-deficit/hyperactivity disorder comorbid with high functioning autism. Methods: A total of 165 children with attention-deficit/hyperactivity disorder (ADHD group), 65 children with attention-deficit/Hyperactivity disorder comorbid with high functioning autism (ADHD-HFA group), and 84 healthy controls (control group) (based on the criteria of DSM-5) were recruited from the Outpatient Clinic of Child Healthcare Department of Shen Zhen Children's Hospital. The Rey complex figure test (RCFT), trail making test (TMT), Stroop color-word test were used to assess working memory, shifting and inhibition. Results: ADHD group (2.1±1.9, 7±5, 2.1±2.0 and 7±5) and ADHD-HFA group (2.0±2.0, 7±6, 2.0±2.1 and 6±5) performed worse than control group (3.4±2.0, 10±5, 3.4±2.0 and 10±6) in Rey complex figure test (all P<0.05). ADHD group ((171±8) s, (27.40±0.82) s and (52.29±1.62) s) and ADHD-HFA group ((197±11) s, (29.7±1.1) s and (58.6±2.1) s) group took longer time on the TMT-2, Stroop2 and Stroop4 test than control group ((135±18) s, (22.4±1.9) s and (38.7±3.8) s) (all P<0.05). In children with low intelligence quotient (IQ), ADHD group ((30±8) s) and ADHD-HFA group ((34±9) s) performed worse on Stroop3 test than control group ((20±4) s) (all P<0.05). In children with average IQ, ADHD group ((19±5) s and (24±8) s) took longer time on the Stroop1 and Stroop3 test than control group ((16±3) s and (19±4) s) (all P<0.05). In children with high IQ, ADHD-HFA group ((20±8) s) spent more time on Stroop1 than control group ((15±4) s) (P<0.05). Inattention symptoms were associated with the time on TMT-2 of ADHD-HFA group (r=0.275 and 0.329, all P<0.05). The score of item 1 in autism spectrum screening questionnaire (ASSQ) was negatively correlated with immediate recall structure and detail scores as well as delay structure scores of Rey complex figure test (r=-0.358, -0.326 and -0.306, all P<0.05). The score of item 4 was positively correlated with errors of Stroop4 (r=0.296, P<0.05). The score of item 22 was positively correlated with time of color interference (r=0.279, P<0.05). Conclusions: Children with ADHD-HFA are likely to demonstrate the spatial working memory, shifting and inhibition deficits associated with ADHD alone. Some domains of executive function impairment in ADHD-HFA group are related with symptoms of inattention/hyperactivity and autism.