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Article: Attention-Deficit/Hyperactivity Disorder (AD/HD)
- Article from:
- Gale Encyclopedia of Children's Health: Infancy throughAdolescence
- Author:
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Attention-deficit/Hyperactivity disorder (AD/HD)
Definition
Attention-deficit/hyperactivity disorder (AD/HD) is a neurobiological disorder characterized by hyperactivity, impulsive behavior, and the inability to remain focused on tasks or activities.
Description
AD/HD, also known as hyperkinetic disorder (HKD) outside of the United States, is estimated to affect 3
–
7 percent of school-aged children, and seems to afflict boys more often than girls. However, the prevalence in boys may be cited because often girls are not diagnosed until later in age. Although difficult to assess in infancy and toddlerhood, signs of AD/HD may begin to appear as early as age two or three, ...