Evidence against Barkley's hypothesis of the centrality of behavioral disinhibition in the genesis of ADHD (Russell A. Barkley)

This study set out to operationalize, measure, and evaluate the interrelationships among the constructs of Barkley's hybrid model of executive functions (1994, 1997a, 1997b, 1998). This was done by comparing performance on the Frontal Lobe Personality Scale (Paulsen et al., 1995), a measure that was developed from the literature on brain injury, with performance on the Conners' Adult ADHD Rating Scale (CAARS; Conners, Erhardt, & Sparrow, 1999), a well-accepted measure of ADHD symptomatology. A central tenet of Barkley's theory is that the core deficit in ADHD is disinhibition and that this leads to executive dysfunction, which in turn allows behavior to be seen as impulsive and hyperactive. Participants were 227 normal undergraduate students. Partial correlations indicated that symptoms of inattention were more highly predicted by the FLOPS subscale of executive dysfunction, whereas symptoms of hyperactivity/impulsivity were more highly predicted by the disinhibition subscale. In addition, scores on the CAARS ADHD Index correlated more highly with executive dysfunction scores than with behavioral disinhibition scores. These findings cast doubt on Barkley's hypothesis that inattention and hyperactivity/impulsivity are due to a core deficit in behavioral inhibition.