Prospective memory performance in non-psychotic first-degree relatives of patients with schizophrenia: a controlled study.

Fu-Chun Zhou,Gabor S Ungvari,Wei-Min Hou,Chuan-Yue Wang,David H K Shum,Helen F K Chiu,Christoph U Correll,Yu-Tao Xiang,David Man,Deng-Tang Liu,Peter J Mckenna

doi:10.1371/journal.pone.0111562

Abstract

ObjectiveWe aimed at investigating prospective memory and its socio-demographic and neurocognitive correlates in non-psychotic, first-degree relatives (FDRs) of patients with schizophrenia compared to patients with first episode schizophrenia (FES), and healthy controls (HCs).MethodsForty-seven FES patients, 50 non-psychotic FDRs (23 offspring and 27 siblings) of patients with chronic schizophrenia (unrelated to the FES group) and 51 HCs were studied. The Chinese version of the Cambridge Prospective Memory Test (C-CAMPROMPT) was used to measure time-based prospective memory (TBPM) and event-based prospective memory (EBPM) performance. Other cognitive functions (involving respective memory and executive functions) were evaluated with standardized tests.ResultsAfter controlling for basic demographic characteristics including age, gender and educational level, there was a significant difference between FDRs, FES and HCs with respect to both TBPM (F(2,142) = 10.4, p<0.001) and EBPM (F(2,142) = 10.8, p<0.001). Multiple linear regression analyses revealed that lower scores of the Hopkins Verbal Learning Test-Revised (HVLT-R) and the STROOP Word-Color Test (SWCT) contributed to TBPM impairment, while lower educational level and higher scores of the Color Trails Test-2 (CTT-2) contributed to EBPM deficit in FDRs.ConclusionsFDRs share similar but attenuated prospective memory impairments with schizophrenia patients, suggesting that prospective memory deficits may represent an endophenotype of schizophrenia.

Highlights

Schizophrenia is a frequently debilitating illness, manifesting primarily with positive and negative psychotic symptoms and cognitive impairment
prospective memory (PM), defined as ‘‘memory for activities to be performed in the future’’, is usually subdivided into time-based PM (TBPM) and event-based PM (EBPM) according to the nature of the cue associated with the future intention
148 subjects were included in this study, i.e., 47 first episode schizophrenia (FES) patients, relatives of chronic schizophrenia patients and controls

Summary

Introduction

Schizophrenia is a frequently debilitating illness, manifesting primarily with positive and negative psychotic symptoms and cognitive impairment. Previous studies focused more on retrospective memory (RM; the ability to remember past information), there is an increasing number of studies that addressed the impairment of prospective memory (PM) in schizophrenia. PM, defined as ‘‘memory for activities to be performed in the future’’, is usually subdivided into time-based PM (TBPM) and event-based PM (EBPM) according to the nature of the cue associated with the future intention. TBPM is the ability to remember carrying out an intention at a specific time in the future. EBPM is defined as the ability to remember performing an intended action when a certain cue appears [4]. PM involves both retrospective memory and an executive cognition component [7], allowing retrieval of the intended content and the specific action that must be executed [8]

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Conclusion