Verbal working memory impairment in schizophrenia patients and their first-degree relatives: evidence from the digit span task.
OBJECTIVE
The evidence for verbal working memory deficits in schizophrenia has been inconsistent. Few studies have evaluated verbal working memory in the first-degree relatives of schizophrenia patients, who likely share the genetic diathesis for schizophrenia but not the potential confounds associated with chronic mental illness.


METHODS
The Wechsler Digit Span Task was used to investigate verbal working memory in 52 schizophrenia patients, 56 of their first-degree relatives, and 73 nonpsychiatric comparison subjects.


RESULTS
The nonpsychotic relatives showed no impairment on the forward digit span task, a measure of general attention, but did show impairment on the backward digit span task, a measure of verbal working memory. Schizophrenia patients showed impairment on both the forward and backward digit span tasks.


CONCLUSIONS
These results indicate that the forward and backward digit span tasks tap different cognitive abilities that are differentially associated with the diathesis for schizophrenia. Working memory deficits associated with schizophrenia appear to be generalized and not limited to the spatial modality.
Conklin
H M
HM
Department of Psychology, University of Minnesota, Minneapolis 55455-0344, USA.
Curtis
C E
CE
Katsanis
J
J
Iacono
W G
WG
D000328:Adult; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D003072:Cognition Disorders / Q000175:diagnosis / Q000235:genetics; D005190:Family; D005260:Female; D020022:Genetic Predisposition to Disease; D006760:Hospitalization; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis* / Q000235:genetics; D008570:Memory, Short-Term; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D012559:Schizophrenia / Q000175:diagnosis* / Q000235:genetics*; D012565:Schizophrenic Psychology; D013647:Task Performance and Analysis; D014705:Verbal Behavior; D014888:Wechsler Scales / Q000706:statistics & numerical data