Comparison of the PPVT-R and WAIS-R in state hospital psychiatric patients

This study examined the relationship between the Peabody Picture Vocabulary Test-Revised (PPVT-R) and Wechsler Adult Intelligence Scale-Revised (WAIS-R) in 40 adult psychiatric inpatients. The tests were administered to the patients in counterbalanced order as part of their overall psychological evaluation. Mean scaled scores were obtained for both tests. There were no significant differences between PPVT-R scores and WAIS-R Verbal, Performance, and Full Scale IQ scores. Significant correlations between the PPVT-R and all three WAIS-R scores also were obtained. However, further analysis indicated a great deal of variability between individual PPVT-R and WAIS-R Full Scale scores. In addition, the PPVT-R was found to underestimate significantly the WAIS-R IQ scores of a subgroup (N = 13) of mildly mentally retarded subjects. A tendency for the PPVT-R to overestimate the WAIS-R as IQ improved also was noted.