MOTOR ASYMMETRY, A NEUROBIOLOGICAL ABNORMALITY IN THE MAJOR PSYCHOSES

A century after Kraepelin, clinical scientists still debate whether th e major functional psychoses, schizophrenia and bipolar illness, are s eparate disease entities or fall on opposite ends of a spectrum of sev ere psychopathology. In a study of control of hand-muscle force, patie nts with schizophrenia and bipolar affective disorder exhibited opposi te asymmetries, with greater right-hand dyscontrol in schizophrenia, a nd greater left-hand dyscontrol in bipolar disorder. This suggests tha t there is greater pathological involvement of the dominant hemisphere in schizophrenia and of the nondominant hemisphere in bipolar disorde r.