Delay discounting of reward in ADHD: application in young children

Background: A key underlying process that may contribute to attention-deficit/hyperactivity disorder (ADHD) involves alterations in reward evaluation, including assessing the relative value of immediate over delayed rewards. This study examines whether children with ADHD discount the value of delayed rewards to a greater degree than typically developing children using a delay discounting task. Methods: Children aged 7-9 years diagnosed with ADHD and controls completed a task in which they chose between a hypothetical $10 available after a delay (7, 30, 90 and 180 days) versus various amounts available immediately. Results: ADHD participants discounted more steeply than controls. However, this effect did not survive covarying of IQ. Conclusions: ADHD is associated with a steeper delay gradient when contemplating hypothetical later rewards, but not independently of IQ. The interplay of cognitive processing and IQ with reward evaluation in ADHD requires further exploration.