A large body of research has focused on the aetiology and treatment of attention deficit hyperactivity disorder (ADHD). However, few studies have systematically investigated longterm outcomes. A small number of North-American studies following clinical samples have found that childhood ADHD is associated with an increased risk of adverse outcomes across domains in adolescence and adulthood. Compared with non-ADHD controls, young people with ADHD have poorer educational, social and mental health outcomes, as well as some physical health problems, such as overweight/ obesity. Yet the factors influencing outcomes in young people with ADHD are poorly understood. Some potential antecedents have been examined, including patient characteristics (such as IQ, comorbid mental health problems and ADHD type, severity and persistence), parent/family factors (such as mental health, ADHD diagnosis, parenting style and socioeconomic status) and treatment variables (such as education programmes and stimulant medication). However, these have mostly been studied in isolation and/or cross-sectionally.