You may know it by the name attention deficit disorder, or ADD. ADD/ADHD makes it difficult for people to inhibit their spontaneous responses—responses that can involve everything from movement to attentiveness. ADHD appears early in childhood.
Children with ADD/ADHD may be:
Inattentive, but not hyperactive or impulsive.
Hyperactive and impulsive, but able to pay attention.
Inattentive, hyperactive, and impulsive (the most common form of ADD/ADHD).
Children who only have inattentive symptoms of ADD/ADHD are often overlooked, as they typically don't cause the behavioral problems that hyperactive children do.
Girls are frequently under-diagnosed with ADHD because they do not cause the behavioral disturbances that boys with ADHD do.