There are at least two ways to provide an epidemiological framework for child neuropsychiatry. The first is to find some reasonable overall boundary for child neuropsychiatry and establish what proportion of all child psychiatric disorders or of all children and adolescents have a neuropsychiatric component. The other is to review the various epidemiological studies which have tried to establish prevalence figures for specific syndromes.

In this overview, I shall attempt both approaches, even though I shall rely on the second one in trying to establish the boundaries of child neuropsychiatry within the broader field of child and adolescent psychiatry.

In defining child neuropsychiatry in Chapter 1, I included the following criteria.

1. Problem onset in infancy, childhood or adolescence.

2. Major mental, emotional or behavioural impairment is the most important clinical problem during at least one phase of development.

3. Important biological contributory factors are present in the genesis of the disorder or the shaping of symptomatology.

In deciding which disorders belong to this field, some, at the present stage, appear to be uncontended candidates, whereas others are likely to cause some dispute. In the first of these categories, mental retardation and other severe learning disorders, autism and the syndromes contained in the behavioural phenotype category, are the most obvious examples. Obsessive compulsive disorders, paranoid disorders and, in particular, anorexia nervosa, on the other hand, make borderline candidates. Some researchers and clinicians would certainly jump at the suggestion of including them among the child neuropsychiatric conditions.