Objective To investigate the distinctive Wechsler cognitive characteristics of children with high-functioning autism spectrum disorder (HF-ASD), attention-deficit/hyperactivity disorder (ADHD), and their comorbidity (HF-ASD+ADHD).

Methods The Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) assessment results of 224 children aged 6-14 years who attended the Child Development and Behavior Center of the Third Affiliated Hospital of Sun Yat-sen University between July 2023 and July 2024 were retrospectively collected, including 48 children in the HF-ASD group, 68 in the ADHD group, 53 in the HF-ASD+ADHD group, and 55 in the typically developing (TD) group. Statistical analyses were performed using one-way analysis of variance (ANOVA), effect size analysis, and linear discriminant analysis.

Results Statistically significant differences were observed among the four groups in all 10 WISC-IV subtests and four composite index scores (all P ＜ 0.001). The HF-ASD group demonstrated relatively preserved performance on the Verbal Comprehension Index (VCI), but showed deficits in Perceptual Reasoning and Working Memory. The ADHD group exhibited poorer performance in Working Memory and Processing Speed. The HF-ASD+ADHD group showed a pattern of dual cognitive deficits. Pairwise comparisons showed a significant difference in the Verbal Comprehension Index between the HF-ASD and TD groups (P = 0.002), and a significant difference in the Working Memory Index between the ADHD and TD groups (P ＜ 0.001). Linear discriminant analysis demonstrated that the Block Design, Similarities, Digit Span, Coding, and Letter-Number Sequencing subtests had the greatest discriminatory value, with an overall classification accuracy of 45.8%.

Conclusion Children with HF-ASD and ADHD exhibit distinct patterns of cognitive characteristics, whereas those with HF-ASD+ADHD present with more severe cognitive impairment. Analysis of WISC-IV subtest profiles can effectively differentiate HF-ASD, ADHD, and their comorbidity.