Handedness in children of schizophrenic parents: data from three high-risk studies.

This is the first report of data analyses from a consortium of longitudinal genetic-risk studies on offspring of schizophrenic parents (CLOSSER) who were followed from birth or mid-childhood to their early 20's or considerably older ages. Three of the CLOSSER studies provide data to enable us to address long-persisting questions in the schizophrenia literature concerning possible atypicality of hand dominance associated with the illness. Handedness, used as a proxy for cerebral lateralization, is a topic of considerable importance because of its potential to reveal mechanisms in the underlying pathophysiology of schizophrenia. We examine agreement among the CLOSSER studies with respect to possible deviance in handedness in subjects with schizophrenic parents (high-risk individuals) and specifically in those who have gone on to develop adult schizophrenia, compared with other subjects of these studies. Possible developmental delay in age at lateralization is also considered.