Abstract
Individuals with attention deficit/hyperactivity disorder （ADHD） may exhibit autism spectrum disorder （ASD） characteristics, even without a formal ASD diagnosis. In this study, we aimed to investigate the clinical features of ADHD in adults according to the strength of their ASD traits. We included 96 adults diagnosed with ADHD who attended an ADHD-specialized outpatient clinic at Showa University Karasuyama Hospital. Autism trait severity, ADHD symptoms, and cognitive characteristics were assessed using the Autism Spectrum Quotient （AQ）, Conners’ Adult ADHD Rating Scale （CAARS）, and Wechsler Adult Intelligence Scale-III （WAIS-III）, respectively. We divided these participants into two groups according to the cutoff AQ value of 33: high-AQ （n＝30） and low-AQ （n＝66） groups. Next, we compared participants’ background and CAARS and WAIS-III scores between these groups. Furthermore, the WAIS-III subtest scores were compared within each group. The CAARS subscale scores related to impulsivity/emotional instability, DSM-IV hyperactive-impulsive, and ADHD index were significantly higher in the high-AQ group than in the low-AQ group. Conversely, the WAIS-III scores did not differ significantly between such groups. However, in the low-AQ group, the scores for verbal comprehension were significantly higher than those for working memory and processing speed. Therefore, the severity of ASD traits may be associated with the ADHD symptoms. Moreover, differences in functional impairment in ADHD were evident on the basis of the strength of the ASD traits. In conclusion, evaluating the strength of ASD characteristics in patients with ADHD may contribute to the selection of more ASD-inclusive treatment strategies.
