Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder that affects children and can persist into adulthood. The disorder is characterized by inattention, hyperactivity, and impulsivity, which can interfere with daily functioning and academic performance. 

Children with ADHD may have difficulty sustaining attention, completing tasks, following directions, and staying organized. They may be easily distracted, forgetful, and struggle with time management. They may also have difficulty sitting still, engaging in quiet activities, and waiting their turn, and may be perceived as disruptive or impulsive. 

ADHD is typically diagnosed based on a comprehensive evaluation, including a review of the child's medical and developmental history, observation of behavior, and assessment of symptoms.