LATERALITY, MEMORY, AND THOUGHT-DISORDER IN SCHIZOPHRENIA

Numerous observations have suggested that there is a disturbance in la terality in schizophrenia, For example, some reports indicate that lef t-handed schizophrenic patients show more evidence of neurological dys function and more severe symptoms than right-handed schizophrenic pati ents. We have found that formal thought disorder is more severe and mo re common in left-handed than in right-handed schizophrenic subjects. Because subtle cognitive and language disorders have also been associa ted with formal thought disorder in schizophrenia, we hypothesized a p articular relationship between left-hand preference and cognitive dysf unction in a schizophrenic sample. We investigated the nature of conte xt-assisted memory performance and thought disorder in 21 left-handed and 21 right-handed schizophrenic patients individually matched on wor d-recall ability, age, sex, and education. Left-handed schizophrenic p atients were less able to take advantage of increasing context to assi st in word recall. The locus of this performance difference was found in the primacy portion of the serial position curve. Left-handed subje cts also had more evidence of formal thought disorder, specifically th e poverty of content dimension. These results could not be accounted f or on the basis of chronicity or neuroleptic usage. In related researc h we have found evidence for a relationship between context memory and magnetic resonance imaging frontal volume (especially the dorsolatera l division) in schizophrenia. We propose that left-handed schizophreni c patients may suffer from a more pronounced form of selective memory disturbance, possibly related to left-hemisphere disturbance, and may also exhibit more frontal atrophy than closely matched right-handed sc hizophrenic controls.