Biological factors in Attention Deficit Hyperactivity Disorder.

For a number of years, clinicians and researchers have recognized the existence of a subgrouping of children who exhibit chronic and pervasive signs of inattention, impulsivity, and physical restlessness, as well as deficiencies in rule-governed behavior, which deviate significantly from age and gender expectations (Barkley; 1981; Ross & Ross, 1982; Wender, 1971). Since first being identified by Still (1902), this particular pattern of behavioral difficulties has undergone numerous changes in the diagnostic terminology used to describe it. Attention Deficit Disorder (with or without Hyperactivity), Hyperkinesis, Hyperkinetic Reaction of Childhood, Hyperactive Child Syndrome, Minimal Brain Damage, and Minimal Brain Dysfunction are some of the many labels that have been applied to this disorder in the past. With the arrival of the recently revised third edition of the Diagnostic and Statistical Manual (DSM III-R, American Psychiatric Association, 1987), this same behavioral constellation is now known as Attention Deficit- Hyperactivity Disorder (ADHD)