Attention Deficit Hyperactivity Disorder (ADHD) is a prevalent childhood disorder characterized by inattention, hyperactivity, and impulsivity, which can persist into adulthood. It has three subtypes: predominantly hyperactive-impulsive, predominantly inattentive, and combined type, with causes linked to genetic and environmental factors. Diagnosis requires comprehensive evaluation, often involving multiple sources of information, and treatment typically includes medications and therapy to manage symptoms.