Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder that manifests as inattention, hyperactivity, and impulsivity, typically diagnosed in children before age 12. The exact causes remain largely unknown but involve genetic, environmental, and social factors, with symptoms potentially persisting into adulthood. Diagnosis relies on criteria from the DSM-5 and the disorder can significantly impact social, academic, and occupational functioning.