Research On Characteristics And Relevant Factors Of Olfactory Identification Function In Patients With Schizophrenia

Objective:To evaluate the reliability and validity of “Chinese Smell Identification Test”(CSIT)in schizophrenia patients.To explore the characteristics and relevant factors of olfactory function in patients with schizophrenia.Methods:1.The study recruited inpatients with schizophrenia in the Shanghai Mental Health Center and healthy controls who matched the gender,age,and education level with the patients.The two groups were tested for olfactory identification ability through using the CSIT,and 16-item odor identification test from Sniffin' sticks(SS-16)as criterion for validity.The patient group was evaluated for psychotic symptoms using the Positive and Negative Symptom Scale(PANSS),and was assessed for cognitive function by the Montreal Cognitive Assessment Scale(MoCA).Some patients were retested for olfactory function after two weeks.2.Statistical methods: The reliability tests included Cronbach's a coefficient,split-half reliability,and the test-retest reliability;the validity test was employed with the criterion-associated validity.Other statistical methods included descriptive statistics,t-test,chi-square test,nonparametric test,correlation analysis,logistic regression and Receiver operating characteristic curves,etc.Results:1.The study recruited 60 inpatients and 60 healthy controls who matched the gender,age,and education level with the patients.In the combined groups,the Cronbach's a coefficient was 0.794,split-half reliability was 0.820.In patients with schizophrenia,the Cronbach's a of CSIT was 0.722,split-half reliability was 0.766.32 patients were retested CSIT after two weeks,the test-retest reliability was 0.84.106 subjects were tested with SS-16,CSIT scores were positively correlated with SS-16 score(r=0.50,p<0.001).In patient group,the criterion-related validity was 0.47.2.The mean score of “Chinese smell identification test” was 24.5±5.4 points,and the control group was 30.1±5.0 points.The patient group was significantly lower than the control group.Correct response rate differed between two groups in 14 items of CSIT.In patients with schizophrenia,there was a positive correlation between MoCA score and CSIT score(r=0.30,p<0.05).There was a negative correlation between PANSS negative symptoms and CSIT score(r=-0.49,p<0.05).There was no significant correlation between age,gender,smoking history,antipsychotic drug dose,duration of disease and CSIT scores.The area under the receiver operating characteristic curve of the olfactory test was 0.777,when cut-off value was 29 points,the sensitivity of distinguishing schizophrenia patients from healthy controls was 85.0%,and the specificity was 61.7%.The specificity and sensitivity were higher than those of SS-16.For “14-item CSIT for schizophrenia”,the area under the receiver operating characteristic curve of the olfactory test was 0.857,when cutoff value was 10 points,the sensitivity of distinguishing schizophrenia patients from healthy controls was 83.3%,and the specificity was 78.3%.Conclusion:1.“Chinese smell identification test” had good reliability and validity in patients with schizophrenia.Olfactory test result could differentiate between schizophrenia patients and healthy subjects.2.Patients with schizophrenia showed significant impairment of olfactory identification.Olfactory dysfunction was associated with cognitive decline and negative symptoms in patients.