Attention deficit hyperactivity disorder (ADHD) Home A-Z Health Information Health Library A-Z Attention Deficit Hyperactivity Disorder (ADHD) Overview Attention deficit hyperactive disorder (ADHD) is a neurodevelopmental disorder commonly diagnosed in children, though is also identified in adolescents or adults. It is marked by varying levels of inattention, hyperactivity and impulsivity. Causes and risk factors The exact cause of ADHD remains unclear, though several risk factors contribute to its development, including:GeneticsEnvironmental factorsAlcohol and drug use during pregnancyHead injury Types ADHD is typically classified into three types:InattentiveHyperactive-impulsiveCombined Symptoms Other symptoms of ADHD include:Inattention: Easy distractibility, difficulty in sustaining attention, losing things easily, forgetfulness, and difficulty in following instructionsHyperactivity and impulsivity: Difficulty in waiting for one’s turn, fidgety, difficulty in remaining seated, always on the go, frequently interrupts during conversation, difficulty in age appropriate estimation of risk, difficulty working in groups and restlessness Diagnosis ADHD diagnoses is common in children but infrequently detected for the first time in adolescence or adulthood (ADHD in adults). Diagnosis includes a checklist for rating symptoms and obtaining history from parents/caregivers and teachers. Treatment ADHD can be treated through: Behavioural therapyLifestyle changesMedications.