Objectively-Measured Impulsivity and Attention-Deficit/Hyperactivity Disorder (ADHD): Testing Competing Predictions from the Working Memory and Behavioral Inhibition Models of ADHD

    Authors

    J. S. Raiker; M. D. Rapport; M. J. Kofler;D. E. Sarver

    Comments

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    Abbreviated Journal Title

    J. Abnorm. Child Psychol.

    Keywords

    ADHD; Impulsive responding; Working memory; Behavioral inhibition; Commission errors; Executive functions; DEFICIT HYPERACTIVITY DISORDER; CONTINUOUS PERFORMANCE-TEST; STOP-SIGNAL; TASK; EXECUTIVE FUNCTION; CHILDREN; SYMPTOMS; INATTENTION; VALIDITY; BOYS; METAANALYSIS; Psychology, Clinical; Psychology, Developmental

    Abstract

    Impulsivity is a hallmark of two of the three DSM-IV ADHD subtypes and is associated with myriad adverse outcomes. Limited research, however, is available concerning the mechanisms and processes that contribute to impulsive responding by children with ADHD. The current study tested predictions from two competing models of ADHD-working memory (WM) and behavioral inhibition (BI)-to examine the extent to which ADHD-related impulsive responding was attributable to model-specific mechanisms and processes. Children with ADHD (n = 21) and typically developing children (n = 20) completed laboratory tasks that provided WM (domain-general central executive [CE], phonological/visuospatial storage/rehearsal) and BI indices (stop-signal reaction time [SSRT], stop-signal delay, mean reaction time). These indices were examined as potential mediators of ADHD-related impulsive responding on two objective and diverse laboratory tasks used commonly to assess impulsive responding (CPT: continuous performance test; VMTS: visual match-to-sample). Bias-corrected, bootstrapped mediation analyses revealed that CE processes significantly attenuated between-group impulsivity differences, such that the initial large-magnitude impulsivity differences were no longer significant on either task after accounting for ADHD-related CE deficits. In contrast, SSRT partially mediated ADHD-related impulsive responding on the CPT but not VMTS. This partial attenuation was no longer significant after accounting for shared variance between CE and SSRT; CE continued to attenuate the ADHD-impulsivity relationship after accounting for SSRT. These findings add to the growing literature implicating CE deficits in core ADHD behavioral and functional impairments, and suggest that cognitive interventions targeting CE rather than storage/rehearsal or BI processes may hold greater promise for alleviating ADHD-related impairments.

    Journal Title

    Journal of Abnormal Child Psychology

    Volume

    40

    Issue/Number

    5

    Publication Date

    1-1-2012

    Document Type

    Article

    Language

    English

    First Page

    699

    Last Page

    713

    WOS Identifier

    WOS:000305230500004

    ISSN

    0091-0627

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