Lexical knowledge degradation in schizophrenia

This study documents a severe picture naming impairment in a series of 22 chronically hospitalised schizophrenics. The pattern and level of naming impairment were comparable in degree and type to that seen neurological patients with left hemisphere lesions. This deficit was further examined to determine whether it conformed to a disorder affecting access to the lexical representations or some degradation of the stored representations themselves. Patient naming was examined twice (18 months apart) for evidence of consistency and for word frequency effects. The pattern of individual patient performance on these criteria showed that the majority had storage disorders; access disorders alone occurred in only a small minority of patients. A subset of 11 of the same patients that were tested on three occasions (across 30 months) showed the same pattern but further indicated that when access problems are present, they reflect difficulty with deliberate, rather than automatic, access to the lexicon. (C) 2000 Elsevier Science B.V. All rights reserved.