The Royal Australasian College of Physicians (RACP), along with many medical authorities, state that ADHD is a neurobiological condition caused by disordered brain circuitry impacting executive functioning (RACP, 2009), and often requiring specialist medical intervention. The notion of defective executive functioning is central to a theory put forward by Russell Barkley (Barkley, 1997), a long-time expert in the ADHD field. His publications promoting his theory have the highest number of citations under the acronym of ADHD in the Scopus database, suggesting the theory’s impact is considerable. Good theories rest on specific and contestable assumptions. The objective of my research is to scrutinise Barkley’s theory to evaluate the plausibility of ADHD as defective brain circuitry.

I use documentary analysis to systematically evaluate key documents by Barkley and others, to evaluate this theory, according to specified criteria. These criteria are (1) accuracy of description of the behaviours associated with executive functioning and (2) data provided in support of the theory. This latter component requires scrutiny of the instruments and methods used to generate the data, as well as examination of how the data was analysed.

Barkley’s supporting literature makes it clear that his approach is that of a cognitivist. The central assumption of this methodology is one of understanding the brain in mechanistic terms, with information processing analogous to a digital computer. Seemingly, this enables data to be generated and evaluated using the same methods as the natural sciences such as physics. Those methods analyse nonliving objects in closed systems. Those objects consist of internal parts that interact with each other, but these interactions are isolated from their external environments. By contrast, living organisms belong to open systems and are distinguished by characteristics of growth and adaptiveness.

Psychologists, philosophers of science, measurement theorists, statisticians, and neuroscientists have extensively criticised the application of closed system methodologies to understanding psychological phenomena. Nevertheless, Barkley’s theory is supported almost entirely by studies using such methods. Furthermore, his theory appears to have been well accepted within the medical research community, as evidenced by Scopus analysis. But questions arise as to why, and to what extent the field has been misled by adopting this approach.

This presentation will consider documents that Barkley himself relies on to show how his modelling is most likely incorrect. I will argue that the brain and any associated behaviours cannot be understood in mechanistic terms, nor independently of the external environment. I will discuss implications for interventions, both medical and psychosocial, based on this approach. Finally, I will present an alternative view towards understanding ADHD.