Impaired recollection-based episodic memory as a cognitive endophenotype in schizophrenia

ABSTRACT

Introduction

Patients with schizophrenia show impaired recollection but largely preserved familiarity-based episodic memory. This study was done to clarify the endophenotypic nature of recollection and familiarity-based episodic memory in schizophrenia and the role of emotional valence of memoranda and degree of recall confidence in it.

Method

Twenty-five patients with schizophrenia, one unaffected sibling of each patient, and twenty-three healthy controls completed two tasks assessing recollection and familiarity-based processes in episodic memory. In the first task, participants were asked to remember positive, negative, and neutral emotional valence words in a remember–know paradigm. In the second task, in addition to recollection and familiarity-based responses, participants were asked to make confidence judgments about their responses.

Results

Patients with schizophrenia and their first-degree relatives (FDRs) performed poorly on recollection but not familiarity-based responses, compared to healthy controls; performance of first-degree relatives was in between and significantly different from that of both patients and controls. The differences in recollection and familiarity-based responses across the three groups were not moderated by recall confidence judgments or emotional valence of memoranda. Furthermore, there was no correlation between recollection-based memory impairments and duration or severity of illness or current medication exposure.

Conclusions

Impaired recollection-based memory constitutes a potential cognitive endophenotype in schizophrenia. Furthermore, selective impairment of recollection-based, but sparing of familiarity-based, memory in patients and their FDRs supports the distinct nature of recollection and familiarity-based episodic memories.

KEYWORDS:

• Endophenotype
• episodic memory
• familiarity
• recollection
• schizophrenia

Acknowledgments

We thank all the participants for consenting to participate in the present study.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed here.