Attention-deficit/hyperactivity disorder (previously known as attention deficit disorder or ADD) is a neurobehavioral disorder characterized by core symptoms of inattentiveness, distractibility, hyperactivity, and impulsivity. ADHD is thought to be the most common childhood mental health disorder, with estimates of its prevalence in children ranging from 5 to 11 percent. ADHD in adulthood is thought to be less common, with approximately 2 to 5 percent of adults diagnosed.
