These problems usually persist through school years and even into adult life, but many affected individuals show a gradual improvement in activity and attention. Several other abnormalities may be associated with these disorders. Cognitive impairment is common, and specific delays in motor and language development are disproportionately frequent. Secondary complications include dissocial behaviour and low self-esteem. Nevertheless, current evidence favours the separation of a group in which hyperkinesis is the main problem.
Hyperkinetic disorders are several times more frequent in boys than in girls.
Impaired attention is manifested by prematurely breaking off from tasks and leaving activities unfinished. Overactivity implies excessive restlessness, especially in situations requiring relative calm. It may, depending upon the situation, involve the child running and jumping around, getting up from a seat when he or she was supposed to remain seated, excessive talkativeness and noisiness, or fidgeting and wriggling. This behavioural feature is most evident in structured, organized situations that require a high degree of behavioural self-control. The associated features are not sufficient for the diagnosis or even necessary, but help to sustain it.