Attention Deficit Hyperactivity Disorder (ADHD) is a chronic neurodevelopmental condition, characterized by difficulties in behavioural and neurocognitive functioning. Many studies have suggested that some maternal factors during pregnancy are associated with ADHD in the offspring. However, the mechanisms and whether the associations are causal is still unclear. This project will be conducted to understand the impacts of maternal hypertensive disorders during pregnancy on attention deficit hyperactivity disorder (ADHD) in offspring as little is known about this. As ADHD is becoming more prevalent, more research is needed to thoroughly understand factors that may increase risk of this disease. We will investigate the role of hypertension during pregnancy in ADHD using genetic, clinic and questionnaire data from the ALSPAC cohort.