ABSTRACT
The syndrome of childhood hyperactivity and attentional disorder poses several interesting questions. Its aetiology is not known, although many contributing factors have been advanced. The causal relationships existing between its major symptoms of hyperactivity and distractibility remain obscure, and their neural basis even more so. Treatment of hyperactive children with psychomotor stimulant drugs such as amphetamine and methylphenidate (Ritalin) appears paradoxical, but in view of our, by now, considerable understanding of the neurochemical and neural mechanisms by which these drugs act in animals, this link may provide us with a possible clue about the neural systems contributing to childhood hyperkinesis. This article: (i) reviews what is known about the neural mediation of the behavioural effects of psychomotor stimulant drugs; (ii) describes some of the recent evidence suggesting that hyperactivity and attentional disorder can result from altered function in relatively independent catecholaminergic systems; (iii) describes the behavioural and neurochemical effects of rearing rats in social isolation, a treatment which mimicks some of the behavioural effects of stimulant drugs; and (iv) considers the possible relevance of this work for childhood attentional disorder.
