Handedness in psychiatric patients.

Eight hundred psychiatric patients and eight hundred controls completed a handedness preference questionnaire. There was no significant difference in handedness between the two samples, but, contrary to some previous reports, excess of sinistrality was not associated with male sex. The distribution of handedness was similar in neurotics and controls, but among psychotics in general there was a higher proportion of fully right-handed subjects. Among schizophrenics there was a significantly higher proportion of left-handed writers among males than females. There were relatively few left-handed writers of either sex among patients with affective psychosis. Female patients with personality disorders had a significantly higher proportion of mixed handedness than controls. The findings are considered in relation to suggestions that functional psychoses may be associated with asymmetrical cerebral dysfunction, and that poorly lateralized function may be related to anomalous psychological development.