Distinguishing familiarity-based from source-based memory performance in patients with schizophrenia.
BACKGROUND
There is substantial current interest in the cognitive deficits associated with schizophrenia, particularly those in the realm of memory. Yet the exact nature of these deficits remains a matter of some debate. This study sought to examine performance on two distinct aspects of memory performance: familiarity-based and source-based memory processes.


METHODS
Eighteen medicated outpatients with schizophrenia and eighteen healthy adult control subjects performed an external source memory task. Key measures included the ability to distinguish old (previously experienced) items from new items, the ability to correctly identify the source (male voice or female voice) of previously experienced items, and the reaction time associated with these responses.


RESULTS
Patients with schizophrenia showed an impaired ability to distinguish old from new items, but intact performance in correctly identifying the source of items recognized as old. Whereas control subjects showed a rapid response to items deemed unfamiliar, particularly in rejecting novel items, these responses were slowed in patients with schizophrenia. This was not attributable to a generalized diminution in processing speed, as reaction times to correctly recognized old items (regardless of source accuracy) did not differ between the two groups.


CONCLUSIONS
Patients with schizophrenia demonstrated impaired familiarity-based and intact source-based memory performance. In addition, the reaction time for novelty detection, an important component of familiarity-based memory, was significantly delayed in patients compared to controls, while the response times for source-based decisions were completely overlapping. Considered together, these findings suggest a deficit in the familiarity-based aspect of episodic memory in at least some patients with schizophrenia.
Weiss
Anthony P
AP
Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA. aweiss@partners.org
Goff
Donald C
DC
Duff
Margaret
M
Roffman
Joshua L
JL
Schacter
Daniel L
DL
D000328:Adult; D001245:Association Learning; D001288:Attention; D002908:Chronic Disease; D003072:Cognition Disorders / Q000175:diagnosis* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall; D008875:Middle Aged; D009483:Neuropsychological Tests; D011930:Reaction Time; D011932:Reading; D012559:Schizophrenia / Q000175:diagnosis*; D012565:Schizophrenic Psychology; D013061:Speech Acoustics; D013067:Speech Perception; D014706:Verbal Learning