ADHD is a common neurodevelopmental disorder characterized by inattention, hyperactivity, and impulsivity. It affects about 5% of children worldwide, with boys being diagnosed three times as often as girls. There are three main presentations of ADHD - predominantly inattentive, predominantly hyperactive/impulsive, and combined type. Diagnosis involves ruling out other possible causes and observing symptoms cross several environments. Treatment typically involves medication, behavioral therapy, and educational accommodations to help manage symptoms and improve functioning.