|This group of disorders is characterized by: early onset; a combination of overactive, poorly modulated behaviour with marked inattention and lack of persistent task involvement; and pervasiveness over situations and persistence over time of these behavioural characteristics.|
|It is widely thought that constitutional abnormalities play a crucial role in the genesis of these disorders, but knowledge on specific etiology is lacking at present. In recent years the use of the diagnostic term "attention deficit disorder" for these syndromes has been promoted. It has not been used here because it implies a knowledge of psychological processes that is not yet available, and it suggests the inclusion of anxious, preoccupied, or "dreamy" apathetic children whose problems are probably different. However, it is clear that, from the point of view of behaviour, problems of inattention constitute a central feature of these hyperkinetic syndromes.|
|Hyperkinetic disorders always arise early in development (usually in the first 5 years of life). Their chief characteristics are lack of persistence in activities that require cognitive involvement, and a tendency to move from one activity to another without completing any one, together with disorganized, ill-regulated, and excessive activity. 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. Hyperkinetic children are often reckless and impulsive, prone to accidents, and find themselves in disciplinary trouble because of unthinking (rather than deliberately defiant) breaches of rules. Their relationships with adults are often socially disinhibited, with a lack of normal caution and reserve; they are unpopular with other children and may become isolated. Cognitive impairment is common, and specific delays in motor and language development are disproportionately frequent.|
|Secondary complications include dissocial behaviour and low self-esteem. There is accordingly considerable overlap between hyperkinesis and other patterns of disruptive behaviour such as "unsocialized conduct disorder". 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. Associated reading difficulties (and/or other scholastic problems) are common.|
The cardinal features are impaired attention and overactivity: both are necessary for the diagnosis and should be evident in more than one situation (e.g. home, classroom, clinic).
Impaired attention is manifested by prematurely breaking off from tasks and leaving activities unfinished. The children change frequently from one activity to another, seemingly losing interest in one task because they become diverted to another (although laboratory studies do not generally show an unusual degree of sensory or perceptual distractibility). These deficits in persistence and attention should be diagnosed only if they are excessive for the child's age and IQ.
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. The standard for judgement should be that the activity is excessive in the context of what is expected in the situation and by comparison with other children of the same age and IQ. 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. Disinhibition in social relationships, recklessness in situations involving some danger, and impulsive flouting of social rules (as shown by intruding on or interrupting others' activities, prematurely answering questions before they have been completed, or difficulty in waiting turns) are all characteristic of children with this disorder.
Learning disorders and motor clumsiness occur with undue frequency, and should be noted separately when present; they should not, however, be part of the actual diagnosis of hyperkinetic disorder.
Symptoms of conduct disorder are neither exclusion nor inclusion criteria for the main diagnosis, but their presence or absence constitutes the basis for the main subdivision of the disorder (see below).
The characteristic behaviour problems should be of early onset (before age 6 years) and long duration. However, before the age of school entry, hyperactivity is difficult to recognize because of the wide normal variation: only extreme levels should lead to a diagnosis in preschool children.
Diagnosis of hyperkinetic disorder can still be made in adult life. The grounds are the same, but attention and activity must be judged with reference to developmentally appropriate norms. When hyperkinesis was present in childhood, but has disappeared and been succeeded by another condition, such as dissocial personality disorder or substance abuse, the current condition rather than the earlier one is coded.