Attention deficit hyperactivity disorder |Classification and
external resources| Children with ADHD find it more difficult to
focus and to complete their schoolwork. Attention deficit-
hyperactivity disorder (ADHD) also known as hyperkinetic
disorder (HKD) is a mental disorder or neurobehavioral disorder
characterized by either significant difficulties of inattention
or hyperactivity and impulsiveness or a combination of the two.
According to the Diagnostic and Statistical Manual of Mental
Disorders (DSM-IV-TR), symptoms emerge before seven years of
age. There are three subtypes of the disorder which consist of
it being predominantly inattentive (ADHD-PI or ADHD-I),
predominantly hyperactive-impulsive (ADHD-HI or ADHD-H), or the
two combined (ADHD-C). Often people refer to ADHD-PI as
"attention deficit disorder" (ADD), however, the latter has not
been officially accepted since the 1994 revision of the DSM.
ADHD impacts school-aged children and results in restlessness,
acting impulsively, and lack of focus whic