HANDEDNESS IN 1ST-EPISODE PSYCHOTIC-PATIENTS AND THEIR 1ST-DEGREE BIOLOGICAL RELATIVES

We evaluated the handedness of 58 schizophrenia patients and 54 of the ir relative, 23 patients with major depression with psychosis and 24 o f their relatives, 36 patients with bipolar psychosis and 33 of their relatives, and 119 nonpsychiatric subjects and 42 of their relatives. Computerized tomography measures were also available for a subset of t he psychotic patients. The schizophrenia patients were significantly m ore left-handed than any of the other groups, and increased sinistrali ty was also associated with larger lateral ventricle to brain area rat ios. The relatives of the schizophrenia patients did not significantly differ on handedness from either the relatives of the affective psych osis patients or the nonpsychiatric subjects. Our findings do not supp ort the notion that left-handedness in schizophrenia is genetically in fluenced. More research with larger family member data sets is warrant ed to further explore this possibility.