Beyond Attention-Deficit Hyperactivity Disorder: Exploring Psychiatric Comorbidities and Their Neuropsychological Consequences in Adults

Objectives: This study aimed to identify the psychiatric comorbidity status of adult patients diagnosed with attention-deficit hyperactivity disorder (ADHD) and determine the impact of comorbidities on neuropsychological outcomes in ADHD. Methods: The study participants were 124 adult patients with ADHD. Clinical psychiatric assessments were performed by two board-certified psychiatrists in accordance with the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. All participants were assessed using the Mini-International Neuropsychiatric Interview Plus version 5.0.0 to evaluate comorbidities. After screening, neuropsy-chological outcomes were assessed using the Comprehensive Attention Test (CAT) and the Korean version of the Wechsler Adult Intelligence Scale, Fourth Edition (K-WAIS-IV). Results: Mood disorders (38.7%) were the most common comorbidity of ADHD, followed by anxiety (18.5%) and substance use disorders (13.7%). The ADHD with comorbidities group showed worse results on the Perceptual Organization Index and Working Memory Index sections of the K-WAIS than the ADHD-alone group (p=0.015 and p=0.024, respectively). In addition, the presence of comorbidi-ties was associated with worse performance on simple visual commission errors in the CAT tests (p=0.024). Conclusion: These findings suggest that psychiatric comorbidities are associated with poor neuropsychological outcomes in adult patients with ADHD, highlighting the need to identify comorbidities in these patients.