Attention Deficit Hyperactivity Disorder (ADHD), is a mental health disorder that affects both children/teenagers and adults. It involves difficulties with inattention (such as difficulty focusing, following through, organising, often forgetting or losing things), impulsivity/hyperactivity (such as moving constantly or feeling restless, difficulty regulating emotions, saying or doing things without thinking them through, interrupting) or both, that interfere with functioning at home, school work or in social situations. You can find out more about ADHD here.