Declarative and nondeclarative memory in schizophrenia: What is impaired? What is spared?

Abstract

The study's aim was to assess a broad range of declarative and nondeclarative memory functions in schizophrenia to identify areas of impairment versus relative preservation. Participants included 40 schizophrenia outpatients and 30 demographically comparable community residents. All participants were administered a battery assessing declarative memory (verbal learning, working memory, semantic memory, remote memory, verbal retention) and nondeclarative memory (procedural learning, priming). To control for order effects, the battery was divided into three parts of approximately equal length with order of administration counterbalanced across study participants. The results showed persons with schizophrenia to be significantly impaired relative to community residents in verbal learning, working memory, semantic memory, remote memory, and priming. In contrast, the two groups were comparable in verbal retention and procedural learning. In the schizophrenia group, priming ability best discriminated past year's vocational status. In sum, the findings indicate a specific pattern of impairment and preservation of memory functioning in schizophrenia. Skill (procedural) learning and retention of learned, declarative verbal information across a delay appear intact, while all other areas measured appear impaired.

Keywords:

• Memory
• Neurocognition
• Schizophrenia
• Declarative memory
• Nondeclarative memory

This project was supported, in part, by a grant from the Stanley Medical Research Institute (R. Kern, Principal Investigator). The authors wish to thank Sharon S. Mitchell for her coordinating efforts and assistance with manuscript preparation, as well as the patients and staff at the San Fernando Mental Health Center (SFMHC) and the Department of Veterans Affairs Greater Los Angeles Healthcare System (VAGLAHS) for their respective participation and support. The title of this manuscript was adapted from an earlier publication (Clare et al., 1993. Memory in schizophrenia: What is impaired and what is preserved?) with credit to L. Clare and her colleagues for its originality.