Domain‐Specific Cognitive Vulnerabilities in ADHD: The Impact of Comorbid Specific Learning Disorder on WISC‐IV Profiles
Öznur Adıgüzel Akman, Ceyda BıyıklıABSTRACT
Aim
Attention‐deficit/hyperactivity disorder (ADHD) is associated with heterogeneous cognitive profiles, yet the extent to which comorbid Specific Learning Disorder (SLD) contributes to domain‐specific cognitive variability remains unclear. This study aimed to examine Wechsler Intelligence Scale for Children–Fourth Edition (WISC‐IV) index‐level cognitive profiles in children with ADHD and to evaluate the independent impact of comorbid SLD using regression‐based and discriminative analyses.
Materials and Methods
This retrospective study included 105 children aged 6–16 years diagnosed with ADHD in a clinical setting. Cognitive functioning was assessed using WISC‐IV index scores (Verbal Comprehension, Perceptual Reasoning, Working Memory, and Processing Speed). Group comparisons were conducted based on the presence of comorbid SLD. Pearson correlation and multiple linear regression analyses were performed to identify independent predictors of cognitive performance. In addition, receiver operating characteristic (ROC) analysis was used to assess the discriminative utility of cognitive indices.
Results
Working Memory Index (WMI) scores were the lowest among all WISC‐IV domains. Children with ADHD and comorbid SLD demonstrated significantly lower scores in Verbal Comprehension, Perceptual Reasoning, and Working Memory compared with those with ADHD alone ( p < 0.05), whereas the between‐group difference in Processing Speed did not reach statistical significance. Regression analyses confirmed that SLD was independently associated with lower Perceptual Reasoning and Working Memory scores. Despite statistically significant group differences, effect sizes were modest and ROC analysis indicated limited discriminative performance (AUC = 0.58). These differences, however, were modest in magnitude.
Conclusions
These findings suggest that comorbid SLD in children with ADHD is associated with a domain‐specific pattern of cognitive vulnerability, with working memory emerging as the most prominently affected cognitive domain, rather than reflecting a generalized cognitive impairment. However, the modest effect sizes and limited discriminative utility indicate that these differences should be interpreted as clinically informative rather than diagnostically definitive. This study highlights the importance of domain‐specific cognitive assessment in clinically referred ADHD populations.