Thought disorder in children at risk for psychosis.

The Thought Disorder Index, which has been shown to be a reliable and valid measure of the degree of thought disorder in adult psychotic patients, was used to assess thought disorder in children. Normal children aged 5 to 16 years, hospitalized psychotic children, children hospitalized for nonpsychotic behavioral problems, and children born to a psychotic mother (high-risk) were tested. In the normal sample, thought disorder decreases with age. The level of thought disorder in psychotic children and high-risk children was about three times higher than that of the normal children, whereas the level of thought disorder of the nonpsychotic hospitalized children was no different from that of the normal children. The study also detected differences in the kinds of thought disorder that characterize the psychotic and high-risk groups vs the other children. The presence of thought disorder may be thought of as a useful indicator of the diathesis for functional psychosis. The Thought Disorder Index merits selection as a tool for investigating thought disorder as a potential precursor variable in studies of children at risk for schizophrenia and manic-depressive illness.