The effects of depressive symptoms on cognitive performance of children diagnosed with attention deficit/hyperactivity disorder

OBJECTIVE: This study aimed to evaluate the effects of comorbid Major Depressive Disorder (MDD) on the neuropsychological functioning of children and adolescents with a primary Attention Deficit/Hyperactivity Disorder (ADHD) diagnosis. METHODS: This retrospective chart review assessed the records of 257 children and adolescents, comparing those with ADHD only (n = 218) and those with ADHD comorbid with MDD (n = 39). Neuropsychological functions were evaluated using WISC-R IQ scores, Reading Speed, and Trail Making Test (TMT) A and B forms. RESULTS: The ADHD+MDD group was significantly older than the ADHD group. When controlling for age, comorbid MDD significantly increased child-reported depression and anxiety symptoms, as well as clinician-rated severity. However, after age control, comorbid MDD did not have a significant effect on overall cognitive performance on WISC-R IQ indices, TMT-derived executive function metrics, or reading speed. Dimensional analyses showed that clinician-rated symptom severity (CGI-S) negatively correlated with reading speed and positively with TMT-B + TMT-A duration. CONCLUSION: ADHD with MDD comorbidity is associated with increased subjective distress and family disruption but does not lead to objective neuropsychological impairment in broad cognitive domains. This finding may reflect the potential floor effects of core ADHD impairments. Treatment should focus on integrated multi-informant interventions to mitigate long-term academic and social costs.