The Effects of Methylphenidate on Cognitive Function in Children with Attention–Deficit/Hyperactivity Disorder

Abstract

Focusing on behavioral criteria for attention-deficit/hyperactivity disorder (ADHD) diagnosis leads to considerable neuropsychological profile heterogeneity among diagnosed children, as well as variable response to methylphenidate (MPH) treatment. Documenting "cold" executive working memory (EWM) or "hot" self-regulation (SR) neuropsychological impairments could aid in the differential diagnosis of ADHD subtypes and may help to determine the optimal MPH treatment dose. In this study, children with ADHD inattentive type (n = 19), combined type (n = 33), and hyperactive-impulse type (n = 4) underwent randomized controlled MPH trials; neuropsychological, behavioral, and observational data were collected to evaluate the children's responses. Those with moderate or significant baseline EWM/SR impairment showed robust MPH response, whereas response for those with lower baseline impairment was equivocal. Implications for medication use and titration, academic achievement, and long-term treatment efficacy are examined.

Reconsidering “Inattention” in Attention-Deficit Hyperactivity Disorder: Implications for Neuropsychological Assessment and Intervention

“…Unfortunately, using behavioral criteria alone in ADHD diagnoses leads to substantial neuropsychological heterogeneity, and this could explain why stimulant medication response is not uniform across treated children with ADHD (Hale et al, 2011). Children with ADHD who have significant EF impairments tend to demonstrate stronger response to medication than do children without EF deficits (Kubas et al, 2012). It is possible that many children diagnosed with ADHD who do not respond to medication may not have the EF impairments that are affected positively by stimulantsdespite the presence of clear behavioral symptoms of ADHD such as inattention.…”

“…Such behavior-rating advocates use the limited-to-poor correlations between neuropsychological EF tests and ADHD behavior ratings as evidence to support their positions that behavior ratings are more useful in ADHD diagnosis (e.g., Barkley & Murphy, 2010). We have also found these limited correlations in our own carefully diagnosed children with ADHD (physician and independent psychologist verification using informant report and rating scale criteria) who have been referred for double-blind placebocontrolled trials of methylphenidate (MPH; e.g., Hale et al, 2011;Kubas, Backenson, Wilcox, Piercy, & Hale, 2012; see Table 1). …”

“…Although the use of ADHD behavioral criteria remains the current standard-of-care diagnostic method and can provide relevant information regarding the child's behavior, practitioners may also benefit from administering a test battery sensitive to ADHD neuropsychological symptoms. Attending to both neuropsychological and behavioral MPH response could guide MPH titration and other intervention practices, which in turn could lead to improved cognitive, academic, and behavioral outcomes for children with ADHD, especially given that the best dose for cognition appears to be lower than the best dose for behavior in good MPH responders (Hale et al, 2011;Kubas et al, 2012). Given the profound costs that ADHD can have on academic (e.g., Barkley, 2006) and social (e.g., Miller & Hinshaw, 2010) functioning, the potential added benefit of using more thorough neuropsychological and behavioral evaluation of ADHD and MPH treatment response outweighs the costs, especially if both academic and behavioral long-term treatment efficacy is realized.…”

“…Because MPH response is not uniform in ADHD (Kubas et al, 2012), which can be explained by differential effects of stimulants on FSC function (Schmeichel & Berridge, 2013), determining the children most likely to benefit from MPH treatment is essential for practitioners and parents alike. Results suggest that while children with behaviorally defined ADHD Combined type are more likely to respond to MPH than those with the Inattentive type, it was the cool dorsal and hot ventral neuropsychological test results that were the strongest indicators of MPH responsive.…”

An evaluation of the pharmacokinetics of methylphenidate for the treatment of attention-deficit/ hyperactivity disorder

“…Moreover robust cognitive and behavioral MPH response was achieved for children with significant neuropsychological baseline impairment, yet response remained poor for those with adequate neuropsychological function prior to treatment [94,95].…”