A Study Of Reality Monitoring Deficiency In Early Schizophrenia

[Background & Objectives] Reality monitoring is the process to distinguish internally generated information from information that originated in the outside world,and it is the basis for maintaining self-awareness.Previous studies on chronic patients have confirmed that reality monitoring defects are common in schizophrenia,and may be an intermediate trait vulnerability marker and risk factor of the disease.Our study aims to explore whether reality monitoring defects has appeared obviously in the early stage of disease,to understand the relationship between reality monitoring ability and patients’ cognitive function,clinical symptoms and types of stimulus materials,and to describe the changes of realistic monitoring defects in the continuum of psychotic disease.[Methods] In the current study,participants from first-episode schizophrenia,clinical high-risk for psychosis and health control groups were recruited after evaluated by Structured Clinical Interview for DSM-IV Patient Edition(SCID-I/P)or Non-Patient Edition(SCID-I/NP)and Structured Interview for Psychosis High Risk Syndrome(SIPS).The study were conducted with 36 FES,58 CHR and 56 HC.Then the Positive and Negative Syndrome Scale(PANSS)was used in the FES group and the Scale of Psychotic-risk Syndromes(SOPS)was used in the CHR group for assessment of clinical symptoms.All the three groups were tested cognitive function using MATRICS Consensus Cognitive Battery(MCCB).At last,all the all the three groups participated in two types of reality monitoring experiments: the classic word-pairing paradigm and the image-pairing paradigm which was originally created and used for the first time in our study.ROC analysis was used to test the discriminant ability of the two paradigms in reality monitoring indicators for patients with first-episode schizophrenia.Nonparametric test,t-test,Spearman correlation analysis and regression analysis were used to explore the relationship between reality monitoring ability and cognitive function,clinical symptoms and types of stimulus materials in early schizophrenia.[Results] Part 1:(1)In the reality monitoring experiments of classic word-pairing paradigm,there were significant differences between the FES and HC groups in the following reality monitoring indicators: total accuracy(p’=0.021),missing rate(p′=0.000),recall of perceive condition(p′=0.019),internalization bias(p′=0.006),recall of imagine condition(p′=0.001).There were no significant differences between CHR and HC groups.However,there was no significant difference in recall of perceive condition between CHR and FES groups among various indicators that differed between FES and HC groups.(2)Multiple linear regression analysis showed that the reality monitoring ability was correlated with some MCCB items: recall of perceive condition correlated with BACS SC(β=0.0241,p=0.0002)and BVMT-R(β=0.0275,p=0.0251),internalization bias correlated with WMS-III SS(β=0.0128,p=0.0160)and HVLT-R(β=0.0065,p=0.0308),recall of imagine condition correlated with BACS SC(β=0.0351,P =0.0046)and externalization bias correlated with BACS SC(β=0.0047,p=0.031).(3)There was no significant correlation between the reality monitoring ability of FES and PANSS scores.But there was a significant difference in recall of perceive condition between subgroups of CHR which were peculiar-thinking group(P1score of SOPS≥3)and mild-symptom group(P1 < 3)(p =0.038).Part 2:(1)In the reality monitoring experiments of image-pairing paradigm which was originally created and used for the first time in our study,there were significant differences between the FES and HC groups in the following reality monitoring indicators: missing rate(p′=0.009),recall of perceive condition(p′=0.006),recall of imagine condition(p′=0.003),externalization bias(p′=0.020).There was no significant difference between CHR and HC groups.However,there was no significant difference in the missing rate between CHR and FES in various indicators that differed between FES and HC groups.(2)There were significant differences in spatial memory between FES and HC groups in the experiments of both paradigms(p′=0.003 for wordpairing paradigms,p′=0.020 for image-pairing paradigms),and the ability of spatial memory were significantly correlated with the total accuracy and missing rate of reality monitoring.(3)The results of ROC analysis showed that: AUC value of monitoring for exogenous information was 0.709 and the AUC value of monitoring for endogenous information was 0.736 in the word-pairing paradigms,while the AUC value of of monitoring for exogenous information was 0.686 and the AUC value of monitoring for endogenous information was 0.720 in the image-pairing paradigm.There was no significant difference between the two paradigms on the discriminant ability of the two paradigms in reality monitoring indicators for patients with first-episode schizophrenia(p<0.05).[Conclusion](1)Patients with first-episode schizophrenia have reality monitoring defects compared to health control,suggesting that reality monitoring deficiency is a primary defect which has apeared obviously in the early stage of schizophrenia.The kind of bias in reality mornitoring may be related to the characteristics of the materials.Patients with schizophrenia are more prone to internalization bias in the word-pairing paradigm,and externalization bias in the image-pairing paradigm.(2)Although reality monitoring deficiency is not significant in CHR group compared to health control in our study,but the performances of CHR in the reality mornitoring tasks are not completely different from the FES group.The difference of reality monitoring ability between subgroups divided by clinical symptoms of CHR suggests that reality monitoring deficiency has occurred within the CHR group.There might be a continuous change in reality monitoring ability from health people to CHR and then to FES.(3)In the current study,participants’ reality monitoring ability is correlated with spatial memory in the same experiments and some items of MCCB.There may be some common neural pathways under reality monitoring and other cognitive functions.However,monitoring ability for endogenous information and exogenous monitoring were correlated with different MCCB items,suggesting that there may be different cognitive strategies in the reality monitoring process to recognize internally generated information and information that originated in the outside world.(4)Both the wordpairing paradigm and the image-pairing paradigm show a moderate discriminant ability in reality monitoring indicators for patients with first-episode schizophrenia.