Psychology: What is inhibition deficit theory
According to the inhibitory deficit hypothesis, ..
Several assumptions are important in understanding the initial model as it is applied to ADHD: (1) The capacity for behavioral inhibition begins to emerge first in development, ahead of most or all these four executive functions but possibly in conjunction with the first, nonverbal working memory. (2) These executive functions emerge at different times in development, may have different developmental trajectories, and are interactive. (3) The impairment that ADHD creates in these executive functions is secondary to the primary deficit it creates in behavioral inhibition (improve the inhibition and these executive functions should likewise improve). (4) The deficit in behavioral inhibition arises principally from genetic and neurodevelopmental origins, rather than purely social ones, although its expression is certainly influenced by social factors over development. (5) The secondary deficits in self-regulation created by the primary deficiency in inhibition feed back to contribute further to poor behavioral inhibition given that self-regulation contributes to the enhancement of self-restraint (inhibition). Finally, (6) the model does not apply to those having SCT. The model has been derived from earlier theories on the evolution of human language (Bronowski, 1977), the internalization of speech (Vygotsky, 1966) and the functions of the prefrontal cortex (Fuster, 1997). The evidence for the original model and its application to ADHD were reviewed in the initial text (Barkley, 1997b).
The inhibitory deficit hypothesis predicts that if older adults ..
There is little doubt that poor behavioral inhibition plays a central role in ADHD (see Barkley, 1997b; Nigg, 2001 for reviews). Although important in the progress of our understanding of ADHD, this conclusion still leaves at least two important questions regarding the nature of ADHD unresolved: (1) How does this account for the numerous other associated symptoms and cognitive deficits found in ADHD (described above) and apparently subsumed under the concepts of motor control and executive functioning? (2) How does this account for the involvement of the separate problem with inattention (poor sustained attention) in the disorder? A theoretical model of ADHD developed by the author not only encompasses many of these earlier explanations but may hold the answers to these questions as well as some unexpected directions that future research on ADHD might wish to pursue (Barkley, 1994, 1997a, 1997b, 2001b). The model has been subsequently revised (Barkley, 2012d) to show how deficits in EF can radiate outward to influence the extended phenotype of the individual into several hierarchically arranged levels of increasingly complex adaptive and social functioning.