LACK OF AN ASSOCIATION BETWEEN DELAYED MEMORY AND HIPPOCAMPAL AND TEMPORAL-LOBE SIZE IN PATIENTS WITH SCHIZOPHRENIA AND HEALTHY CONTROLS

The purpose of the present study was to investigate putative neural su bstrates of long-term (delayed) memory in schizophrenia and young heal thy controls. Ten ''low'' and 10 ''high'' memory patients were selecte d from a large sample of DSM-III-R diagnosed schizophrenia spectrum pa tients, based on composite verbal and nonverbal delayed recall memory scores. Ten ''low'' and 9 ''high'' memory individuals were also select ed from a larger sample of young healthy controls. Magnetic resonance imaging scans were acquired on a 1.5-T GE Signa scanner using a SPGR s equence (repetition time = 24 msec, echo time = 5 msec). Hippocampal v olumes were computed from manual tracings (intraclass correlation = .9 6), and temporal lobe and whole brain tissue volumes were obtained usi ng a semiautomated technique. In both the patient sample and controls, there was no significant relationship between delayed memory ability and hippocampal, temporal lobe, or whole brain volume, The integration of results from this study, and from studies on normal aging and Alzh eimer's disease, supports a model suggesting that hippocampal size may be an indicator of long-term memory ability, but only when hippocampa l measures reflect aging and degenerative hippocampal atrophy, If the hippocampal measures reflect individual differences in hippocampal siz e prior to the onset of hippocampal atrophy, then hippocampal size doe s not appear to predict long-term memory ability. (C) 1997 Society of Biological Psychiatry.