Genetics and brain function of children with ADHD

Family, twin, and adoption studies of the last 20 years showed that ADHD is a highly heritable disorder, which indicates a significant genetic component influencing the risk of the disorder. However, although the heritability of ADHD is estimated at about 76% in children and adolescents, it has been challenging to identify individual genes responsible for the development of ADHD due to being a multifactorial disorder in which many genes, all with a small effect, are thought to cause the disorder in the presence of unfavorable environmental conditions.
Impairments in executive functioning are important features of ADHD. Response inhibition, one of the core components of executive functioning, is defined as the ability to stop or postpone a dominant, automatic, or prepotent response. While impaired response inhibition has often been regarded as a primary deficit specific to ADHD, meta-analyses of functional neuroimaging studies investigating the response inhibition in ADHD reported deficits in inhibitory control mediated by fronto-striatal and fronto-parietal neural networks.
As a part of NeuroIMAGE project, Gülhan aimed to investigate possible associations between polygenic risk score for ADHD (PRS-ADHD) and core symptoms of ADHD, and subsequently explore how functional neural correlates of response inhibition during a stop-signal task might explain these associations by mediation analyses. We think that these analyses would be particularly relevant in pathological contexts since selective vulnerability of neural activity in certain brain regions during the stop-signal task might help elucidate the link between PRS-ADHD and potential functional alterations of ADHD associated with response inhibition.