Article 3 [W3] - Dual Pathway Model ADHD

Question 1

Abstract

Answer 1

Psychological accounts have characterised attention-deficit/hyperactivity disorder (AD/HD) as either a neuro-cognitive disorder of regulation or a motivational style.

Poor inhibitory control is thought to underpin AD/HD children’s dysregulation while delay aversion is a dominant characteristic of their motivational style.

A recent ‘head to head’ study of these two accounts suggest that delay aversion and poor inhibitory control are independent co-existing characteristics of AD/HD (combined type). In the present paper we build on these findings to propose a dual pathway model of AD/HD that recognises two quite distinct sub-types of the disorder.

In one, AD/HD is the result of the dysregulation of action and thought resulting from poor inhibitory control associated with the meso-cortical branch of the dopamine system projecting in the cortical control centres (e.g. pre-frontal cortex).

In the other AD/HD is a motivational style characterised by an altered delay of reward gradient linked to the meso-limbic dopamine branch associated with the reward circuits (e.g. nucleus accumbens).

The two pathways are further distinguished at the levels of symptoms, cognitive and motivation profiles and genetic and non-genetic origins.

[Sonuga-Barke, E.J.S. (2002). Psychological heterogeneity in AD/HD—a dual pathway model of behaviour and cognition]

Question 2

Distinguishing between “ADHD as a disorder of regulating action and thought” and “ADHD as a motivational style with acquired cognitive characteristics”

Answer 2

• The motivational style pathway is more likely to vary as a function of environmental context; whereas the disorder thought and action pathway should exist largely independent of context.
• The disordered thought and action pathway is associated with more severe and generalized cognitive impairment (because the cognitive dysregulation associated with poor inhibitory control is compounded by the effects of behavioral symptoms on the child’s opportunity to develop the ability to effectively provide, protect and utilize processing time). For children with the motivational
  style pathway there is potential to develop alternative processing pathways!