Childhood precursors of psychosis as clues to its evolutionary origins.

Those who as adults will be admitted to a psychiatric ward with a psychotic illness can be distinguished (on the basis of group differences) from others by their behaviour and academic performance at the ages of 7 and 11 years. Pre-schizophrenic boys are anxious and hostile towards adults and peers at the age of 7 years and show poor concentration. By age 11 years these boys are also rated as depressed, and pre-schizophrenic girls as depressed and withdrawn. Pre-affective psychotic boys show minor changes (for example an increase in hostility and restlessness) at age 7 years, although these features are not obvious at age 11 years. Abnormalities that in some respects resemble those in pre-schizophrenic boys are present at age 11 years in a group of females who will be admitted to psychiatric units with non-psychotic diagnoses by the age of 28 years. Academic impairments (including speech and reading difficulties) at ages 7, 11 and 16 years are more severe in pre-schizophrenics than in the other groups. Schizophrenics-to-be are slow to develop continence and show poor coordination and vision at age 7 years, and are rated clumsy at age 16 years. Psychosis reflects a disturbance of aspects of central nervous system function that are time-dependent and in certain respects gender specific. It is argued that the psychoses represent extremes of variation in a gene (or genes) that differs between sexes and controls the timing of development of the two cerebral hemispheres.(ABSTRACT TRUNCATED AT 250 WORDS)