Exploratory factor analysis of the WAIS-III in a mixed patient sample

The Wechsler Adult Intelligence Scale-III (WAIS-III) was administered to 152 patients at a VA Medical Center. Means for age, education, and Full Scale IQ were 51.49 years (SD = 13.00), 12.43 years (SD = 2.00), and 92.61 (SD = 14.06), respectively. Of the 152 patients, 69 had substance abuse disorders, 39 had medical/neurological conditions, 27 had both substance abuse and psychiatric disorders, and 17 had psychiatric conditions. The 13 WAIS-III subtests were subjected to a principal-axis factor analysis with oblimin rotation. Four factors were specified to be retained. The Verbal Comprehension, Perceptual Organization, and Processing Speed factors were identical to those in the standardization sample. However, Arithmetic could not be allocated to any factor within the patient sample. The Working Memory factor consisted only of the Digit Span and Letter-Number Sequencing subtests. © 2000 National Academy of Neuropsychology. Published by Elsevier Science Ltd