Are TOPF and WRAT WR Interchangeable Measures among Psychiatric Inpatients?

To examine whether Test of Premorbid Functioning (TOPF) and Wide Range Achievement Test-Word Reading subtest (WRAT WR) are interchangeable measures, and the relationship between these measures and intelligence, among patients with schizophrenia.

In this archival study, the authors examined neuropsychology referrals of an inpatient forensic state hospital. Patients with a schizophrenia spectrum disorder (SSD) who received the Wechsler Adult Intelligence Scale-Fourth Edition or the Wechsler Abbreviated Scale of Intelligence-Second Edition and either TOPF or WRAT WR were considered for inclusion. The final sample consisted of 119 individuals (73.1% male).

Although there was a linear relationship between most TOPF variables and WRAT WR, their concordance was weak (concordance correlation coefficients [CCC] < 0.90). Poor concordance was also observed between current FSIQ and all standard scores (SS) derived from word reading measures. FSIQ-word reading measure discrepancy scores differed significantly from a hypothesized mean of 0 (mean discrepancy range = -7.42 to -16.60). Discrepancies greater than one standard deviation (>1 SD) were highest among demographics-based SS (i.e. TOPF Predicted and Simple without TOPF). Performance-based SS, particularly TOPF Actual and WRAT4 WR, had the fewest discrepancy scores >1 SD fromFSIQ.

TOPF and WRAT WR should not be used interchangeably among institutionalized patients with SSDs. TOPF and WRAT WR were discrepant from FSIQ, with demographic variables producing higher SS relative to performance-based variables. Future research is needed to determine which of these measures more accurately estimates intelligence among inpatients withSSDs.