The Third Edition Of Wechsler Adult Intelligence Scale (Chinese Version): The Contrast Study Between Schizophrenia And Healthy Adults

Objective: 1. To evaluate the construct validity of the special four-factor structure of the WAIS-â…¢Chinese version in a clinical sample of inpatients with schizophrenia as well as a sample of healthy adults. 2. To compare the performance of two study samples on WAIS-â…¢Chinese version in both Verbal Scale IQ, Performance Scale IQ, Full Scale IQ and Verbal Comprehension Index, Perceptual Organization Index, Working Memory Index, Processing Speed Index, as well as in 12 subtests with the understanding of the degree of differences.Methods: The measure consists of verbal IQ, performance IQ and Full IQ with four index scores, underlying 12 subtests in the present study (Picture Completion, Vocabulary, Digit Symbol-Coding, Similarities, Block Design, Arithmetic, Matrix Reasoning, Digit Span, Information, Picture Arrangement, Comprehension, Symbol Search). We recruited 114 patients with schizophrenia (60 were male, 54 were female; minimum of age=17 years, maximum of age=61 years, mean age=32.5 years, SD=10.2; mean education level=10.5 years, SD=2.9), and 114 healthy adults (53 were male, 61 were female; minimum of age=18 years, maximum of age=77 years, mean age=32.8 years, SD=10.3; mean education level=10.6 years, SD=3.2). All the patients were respectively recruited from the Second Xiangya Hospital of Central South University (30%), the Second People's Hospital of Hunan Province (40%), and the Changsha Mental Hospital (30%). Four competing hypothetical models of factors were tested for model fit and parsimony in both research samples, using maximum likelihood confirmatory factor analysis, t test and effect size were applied here to carry on the significance test.Results: 1. Confirmatory factor analysis indicated that Model 4 (WAIS-â…¢) of Verbal Comprehension, Perceptual Organization, Working memory, and Processing Speed was the best model in all alternative models in that it best fit the data from both schizophrenia sample and healthy adults sample, meeting all the criterions, i.e., AGFI>0.8, RMSEA<0.5, TLI and CFI>0.95, and PNFI>0.6. 2. The scores of patients sample exhibited significantly different from that of healthy adults sample in all three IQ and other three indices in addition to Verbal Comprehension Index(P<0.05).The calculation of effect size indicated significant difference with small degree between two study samples in VIQ, significant difference with medium degree in PIQ, FSIQ, POI and WMI and significant difference with larger degree in PSI, as well as the corresponding degree of significant difference in subtests.Conclusions: 1. These empirical analyses and results support the construct validity of WAIS-â…¢Chinese version in patients with schizophrenia and healthy adults in Chinese mainland. 2. There are significantly different between schizophrenia sample and healthy adults sample in most of descriptors, especially a significant difference with higher degree in WMI and PSI, which implied schizophrenia patients have deficits of cognitive functions.