Causes and pathology of early childhood psychoses

In the majority of the studies reported here, the subjects are referred to by the authors as 'autistic'. The criteria for case selection vary. Some authors use a narrow definition of autism based on Kanner's publications, whereas others cover a wider group, but they are all concerned with children in whom the psychosis began before five and, in the great majority, before three years of age (Kolvin, 1971; Kolvin, Ounsted, Humphrey & McNay, 1971).