Sunday, October 31, 2010
ADHD = Different Reward / Motivation Pathway?
More on the evolving story about ADHD biology and reward. Rather than ADHD appearing as a fixed deficit in executive function, increasing evidence suggests that children (and adults) with ADHD behaviors are showing impulsivity mainly in non-reward situations.
In this recent study from Germany, 8-13 year old boys diagnosed with ADHD showed a much greater ability to inhibit impulsive behavior on the go/no-go test if rewards- monetary or social were involved. The differences were striking between the two groups...whereas only 12.5% of the control group slowed down their behaviors and improved their responses in the control group, 43.8% of the ADHD group slowed down their behaviors and exhibited fewer false alarm rates. The implications for findings such as this are significant - if making external or situational changes to a task could eliminate or significantly reduce impulsivity, the impulsivity is not a disease or fixed deficiency, but rather a behavioral response to specific conditions implicit in the task.
The researchers are very careful to not overstate their findings: "given the heterogeneity within the ADHD population,it is arguable that dysregulated reward-seeking behavior alone can account for all cases of ADHD. Nevertheless, reinforcement theories are able to explain most of the ADHD symptoms . ADHD possibly represents the final outcome of diverse and discrete neurodevelopmental
pathways with an 'extreme reward approach pathway' leading to impulsive and overactive behavior."
One might also argue whether the term "extreme" is unduly negative to describe what could be an alternative and not necessarily pathology reward pathway. Why locate the fault in the children? Why not say that 1/4 of the population of children don't respond well in an "understimulated" environment. Why should a child be motivated to perform a meaningless go/no-go task?
So what about the child diagnosed with ADHD whose symptoms are worst with uninteresting (at least to the child) classroom work? Perhaps the rewards of socializing, dodgeball at recess, doodling a design for game, or designing a space ship out of legos are more rewarding (and deserving of focus and care) than Mad Math Minutes? Our prior blog post on fMRI activation patterns for money-induced incentives and ADHD now seem more compelling...
p.s. Data such at this also lend positive support for the use of more extrinsic rewards when tasks are not completed by children with ADHD.
Greater Sensitivity to Social Rewards In Children with ADHD pdf
Eide Neurolearning Blog: Amphetamines Blunt Rewards in Normal Subjects
Eide Neurolearning Blog: Money, Motivation, ADHD, and the Brain