Do Sluggish Cognitive Tempo Symptoms Predict Response to Methylphenidate in Patients with Attention-Deficit/Hyperactivity Disorder-Inattentive Type?

In this naturalistic study, we assessed the effect of sluggish cognitive tempo (SCT) symptoms in the response to methylphenidate (MPH) in 88 children and adolescents with attention-deficit/hyperactivity disorder-Inattentive Type (ADHD-I) according to Diagnostic and Statistical Manual of Mental Disorders, 4(th) edition (DSM-IV) criteria. SCT symptoms were assessed in these subjects by means of the Child Behavior Checklist (CBCL) scale. The response to MPH after 1 month of treatment was assessed by parental scores in the Swanson, Nolan, and Pelham Questionnaire-Version IV (SNAP-IV) scale. No significant differences were found between subjects with and without SCT symptoms in the response to MPH either assessing presence of SCT symptoms categorically (at least 1 symptom) or dimensionally (p<0.5 for both analyses; effect size [ES] = 0.24). Our findings corroborate previous phenotypic data suggesting that SCT symptoms do not define a clinically relevant type of ADHD-I.