Reduced intrasubject variability with reinforcement in boys, but not girls, with ADHD: Associations with prefrontal anatomy

• Motivational contingencies improved response control in boys, not girls, with ADHD.
• Prefrontal cortex (PFC) surface area (SA) was reduced in children with ADHD.
• PFC SA was associated with improvement in response variability with reward in ADHD.
• Different factors may influence response control in boys and girls with ADHD.

This study examined the impact of motivational contingencies (reinforcement and punishment) on go/no-go (GNG) task performance in girls and boys with ADHD relative to typically developing (TD) children and associations with prefrontal anatomy. Children ages 8–12 with ADHD (n = 107, 36 girls) and TD controls (n = 95, 34 girls) completed a standard and a motivational GNG task and associations with prefrontal cortex (PFC) surface area were examined. Intrasubject variability (ISV) was lower during the motivational compared to the standard GNG among TD girls and boys, and boys with ADHD, but not among girls with ADHD. A greater reduction in ISV was associated with greater PFC surface area among children with ADHD. This novel demonstration of improvement in ISV with motivational contingencies for boys, but not girls, with ADHD and associations with PFC anatomy informs our understanding of sex differences and motivational factors contributing to ISV in children with ADHD.