DRD2 and attention deficit-hyperactivity disorder: Moving beyond the behavioural level, by using structural equation modelling in a sample of 421 non-clinical adults, a recent study aimed to gain insight into the genetic mechanisms underpinning ADHD and indices of overeating by genotyping Dopamine receptor D4 and dopamine receptor D2 (DRD4 and DRD2), considering their involvement in ADHD and reward sensitivity [22].