Article

Validity of the Executive Function Theory of Attention-Deficit/Hyperactivity Disorder: A Meta-Analytic Review

University of Denver, Denver, Colorado, United States
Biological Psychiatry (Impact Factor: 10.26). 07/2005; 57(11):1336-46. DOI: 10.1016/j.biopsych.2005.02.006
Source: PubMed

ABSTRACT

One of the most prominent neuropsychologic theories of attention-deficit/hyperactivity disorder (ADHD) suggests that its symptoms arise from a primary deficit in executive functions (EF), defined as neurocognitive processes that maintain an appropriate problem-solving set to attain a later goal. To examine the validity of the EF theory, we conducted a meta-analysis of 83 studies that administered EF measures to groups with ADHD (total N = 3734) and without ADHD (N = 2969). Groups with ADHD exhibited significant impairment on all EF tasks. Effect sizes for all measures fell in the medium range (.46-.69), but the strongest and most consistent effects were obtained on measures of response inhibition, vigilance, working memory, and planning. Weaknesses in EF were significant in both clinic-referred and community samples and were not explained by group differences in intelligence, academic achievement, or symptoms of other disorders. ADHD is associated with significant weaknesses in several key EF domains. However, moderate effect sizes and lack of universality of EF deficits among individuals with ADHD suggest that EF weaknesses are neither necessary nor sufficient to cause all cases of ADHD. Difficulties with EF appear to be one important component of the complex neuropsychology of ADHD.

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Available from: Joel Thomas Nigg, May 27, 2015
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    • "Attention deficit/hyperactivity disorder (ADHD) – one of the most frequently diagnosed disorders in childhood – is characterized by symptoms of age-inappropriate impulsivity, hyperactivity, and inattention [1]. Additionally, many studies have demonstrated that children with ADHD show deficits in executive functions [2], that is, higher cognitive processes including the control and allocation of attentional resources necessary for adaptive planning of behavior [3]. Supporting findings stem from structural and functional neuroimaging studies with children with ADHD showing reduced volumes and metabolic rates in specific brain areas including the frontal lobe, which plays an important role in executive function and attention [4]. "
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    • "Similarly, when compared with typically developing (TD) samples, children and adolescents with ADHD demonstrate widespread EF impairments (for review, see Willcutt et al., 2005). That is, children and adolescents with ADHD experience deficits in inhibitory control (Barkley, Edwards, Laneri, Fletcher, & Metevia, 2001; Hinshaw, Carte, Sami, Treuting, & Zupan, 2002), set shifting (Brewer et al., 2001), and working memory (Barnett et al., 2001), but unlike FASD samples, the most pronounced deficits have been shown for inhibition and working memory, with smaller and less consistent effects for set shifting (Willcutt et al., 2005). "
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    • "Interestingly, the maturation of executive functioning in typically developing individuals parallels the decline in vehicular collisions; both plateau around age 25 (National Highway and Transportation Safety Administration 2008; Zelazo et al. 2004). Additionally, lower levels of executive functioning have been associated with higher frequency of vehicular collisions, and groups at high risk for vehicular collisions (e.g., individuals with ADHD or Depression; Vaa 2014; Bulmash et al. 2006) have been previously identified to have lower levels of executive functioning (Kasper et al. 2012; Snyder 2013; Willcutt et al. 2005). Executive functioning deficits have been well documented in the ASD literature (Hill 2004; Liss et al. 2001; Ozonoff et al. 1991). "
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