High pretreatment cognitive impulsivity predicts response of oppositional symptoms to methylphenidate in patients with attention-deficit hyperactivity disorder/oppositional defiant disorder

The aim of this study was to compare impulsivity levels, as assessed by a continuous performance test (CPT), and the correlations between baseline CPT performance and response to methylphenidate (MPH), as assessed by the conjunctive CPT (CCPT), in children with only Diagnostic and Statistical Manual of Mental Disorders, 5th ed. attention-deficit hyperactivity disorder with no oppositional defiant disorder (ADHD/noODD) or with comorbid ODD (ADHD/ODD). Fifty-three children and adolescents were included in the study (ADHD/noODD group, n = 25, 12 women/13 men and ADHD/ODD group, n = 28, eight females/20 males). Attention was assessed at baseline using CCPT. ADHD and ODD severities were assessed at baseline and following a 12-week MPH treatment using the ADHD-rating scale (ADHD-RS) completed by the parent and by a teacher and the Kiddie-Schedule for Affective Disorders and Schizophrenia for School-Age Children-ODD (K-SADS-ODD) completed by the treating psychiatrist. Higher baseline commission-errors rates (P = 0.0031) in ADHD-RS/parent-child, ADHD-RS/teacher, and K-SADS-ODD scores were detected in ADHD/ODD compared with the ADHD/noODD. Significant improvements in ADHD-RS/parent-child, ADHD-RS/teacher, and K-SADS-ODD scores were achieved following MPH treatment in both groups. Significant correlations were found between baseline CCPT commission-error rates and improvement in ADHD-RS-teacher in ADHD/noODD, but not in ADHD/ODD. Among the ADHD/ODD, but not the ADHD/noODD, a significant correlation was found between baseline CCPT commission-error rates and improvement in K-SADS-ODD. Baseline cognitive impulsivity (as measured by the CCPT) can predict response of ODD to MPH treatment in ADHD/ODD patients.