Left-handedness and thought disorder in the schizophrenias.

The relation between language dysfunction and handedness was examined in a sample of 58 male schizophrenic patients. Severity and type of language dysfunction were assessed using ratings on categories of thought disorder derived from the Schedule of Affective Disorders and Schizophrenia (Spitzer & Endicott, 1977). Hand preferred for writing was the criterion for handedness. In this sample, the incidence of left-handedness was raised and left-handedness was associated with the presence and severity of thought disorder. These findings are congruent with the hypothesis that a sizable proportion of left-handed schizophrenic individuals are left-handed because of a disruption in the pattern of hemispheric dominance that also impairs language functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)