Cause of impulsive choices by kids with ADHD identified in new research

Credit:  Microsoft

Many people with Attention-Deficit/Hyperactivity Disorder (ADHD) make impulsive decisions that are not best for them in the long-term. Now researchers have discovered the exact process responsible for these decisions as well as the point in this process when these decisions are made. Researchers think these discoveries may lead to better treatments for people with ADHD.

People with ADHD often make decisions based on the immediate reward they receive instead of considering any long-term consequences. For example, a person may decide to spend an hour playing a video game instead of practicing for her driving test. In this situation, the person is immediately rewarded because she gets to play her video game. She hasn't considered the long-term value of using the hour for practice that may help her pass her driving test. 

In this study from the University of Zürich, researchers analyszed the decision-making process of 40 adolescents - 20 of whom had ADHD. The study participants played a game "where they had to learn which of two images carried more frequent rewards."  During the game functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) were used to monitor the participants' brain activity.  

ADHD and Problems with Reward Prediction Errors

Researchers discovered that "impaired decision-making and learning mechanisms" in the participants with ADHD was caused by flawed processing of reward prediction errors (RPEs) in the brain, specifically in the medial prefrontal cortex. 

Credit: US Govt Photo

Reward prediction refers to activity of brain cells called neurons.  A reward prediction error occurs when your brain expects you to get a reward, but you do not receive one.  If your brain is not expecting a reward and you receive one this is also a RPE.  For example, if your brain is expecting a piece of cake after a meal and you don't get the cake this is a reward prediction error.

Implications of Study Results

"We were able to demonstrate that young people with ADHD do not inherently have difficulties in learning new information; instead, they evidently use less differentiated learning patterns, which is presumably why sub-optimal decisions are often made", says the first author Tobias Hauser. “If our findings are confirmed, they will provide key clues as to how we might be able to design therapeutic interventions in future.” 

The study, "Role of the Medial Prefrontal Cortex in Impaired Decision Making in Juvenile Attention-Deficit/Hyperactivity Disorder," is published in JAMA Psychiatry.

Sources:

ADHD children make poor decisions due to less differentiated learning processes (University of Zurich)

ADHD children make poor decisions due to less differentiated learning processes (Medical Express)

Role of the Medial Prefrontal Cortex in Impaired Decision Making in Juvenile Attention-Deficit/Hyperactivity Disorder