LATERALIZED HEMISPHERIC DYSFUNCTION IN THE MAJOR PSYCHOTIC DISORDERS - HISTORICAL PERSPECTIVES AND FINDINGS FROM A STUDY OF MOTOR ASYMMETRYIN OLDER PATIENTS

Differences in functioning between the two cerebral hemispheres have b een reported for more than a century. In recent decades, issues relate d to lateralized dysfunction have been raised in psychiatric illnesses such as schizophrenia and bipolar disorder. In particular, evidence s uggests that schizophrenia may be particularly associated with left he misphere dysfunction and bipolar disorder with right hemisphere dysfun ction. We discuss these issues, along with a conceptual framework for integrating hypotheses about the relationship between the major psycho tic illnesses based on a two-dimensional continuum. We also present ne w findings from our study of motor asymmetry in older patients with ps ychosis that support this framework. Our results indicate that schizop hrenia may be associated with left hemisphere pathology to a greater e xtent than right, whereas the reverse may occur in bipolar disorder. ( C) 1997 Elsevier Science B.V.