The Israeli high-risk study: statistical overview and discussion.

We have attempted to provide an overview of the initial evaluation of high-risk and control children. Summary measures of pathology were calculated for each clinical evaluation and objective test of the subjects. Correlational analysis revealed a pattern of intercorrelations among clinical subjective measures of pathology, and among objective measures, with no significant cross-correlations between the two types of measures. The one exception was the presence of neurological soft signs, which tended to correlate with both clinically and objectively measured pathology. Cluster analysis revealed three groups of subjects: a small group of index subjects who performed poorly on both clinical and objective measures; a larger cluster, predominantly index subjects, who showed clinical but not objective pathology; and a third group, including most of the controls, who functioned relatively well on both types of measures. Index subjects tended to show more consistent pathology across both clinical-subjective and objective examinations than controls. We hypothesize that our results stem from underlying deficits in attention, motor function, and perceptual-motor integration in offspring of schizophrenic patients. The finding of an inverse relationship between degree of pathology and age among the index children raises the possibility that developmental lags also play a part in the pathology of our high-risk subjects.