Children with ADHD less able to adapt to changing reward patterns, study

A new study in child psychology finds that children with ADHD (attention-deficit hyperactivity disorder) have a harder time adapting to changes in positive reward systems in comparison with other children.

Researchers in Japan and New Zealand tested 167 children more than half of whom were diagnosed with ADHD and found that when tasked with playing a simple computer game that rewarded the child for correct answers but periodically and without warning shifted the rewarding scheme, those children with ADHD were less likely to adapt their answers accordingly.

“I think this research has important implications for how we manage the behaviour of children with ADHD,” says Gail Pripp, director of the Human Developmental Neurobiology Unit at the Okinawa Institute of Science and Technology Graduate University and co-author of the study.

“What we argue is that, for these children, we need to make explicit what the requirements are in any given situations, so that we are not relying on them to identify what the conditions are, but we are actually explicitly telling them: this is what you will be rewarded for.”

Research has shown that children with ADHD typically find it more difficult to deal with unexpected change and can struggle with open-ended tasks, being less capable at picking out what’s important and what isn’t within new environments. The current research shows that figuring out the rules governing positive reinforcement in a given context -a key feature in many learning situations- can be especially taxing for children with ADHD.

The study asked children to decide whether there were more blue or red faces on a computer screen in front of them and rewarded them with tokens and verbal praise for correct answers. At first, the rewards were higher (more tokens) for correct “blue” answers, then after 20 such interactions the rewards shifted without explanation so that higher rewards came with “red” answers. The typically developing children were found to more quickly change their responses than those with ADHD in order to receive the higher rewards.

“These results may reflect reduced motivation for seeking reinforcement; that is, a reduction in the effect of the reinforcers on response allocation over time,” say the study’s authors, “Or difficulty tracking reinforcement availability following unannounced contingency changes.”

Affecting an estimated five to 12 per cent of school-aged children, ADHD is currently the most common childhood psychiatric disorder diagnosed in Canada. Treatment and management of the condition include parental training, cognitive behavioural therapy and medication, usually in the form of stimulants such as Ritalin or Dexedrine. About half of Canadian children diagnosed with ADHD receive medication.

A new study from the United Kingdom finds that the use of drugs in that country to treat ADHD may have reached a turning point. Where prescriptions for ADHD rose by a factor of eight between 1995 and 2008, the number subsequently fell by a marginal but significant amount between 2008 and 2013, reaching a high of 10.2 new prescriptions per 10,000 children in 2007 and declining to 9.1 per 10,000 children in 2013.

More Cantech Science