The latent structure of cognitive symptom exaggeration on the Victoria Symptom Validity Test.

Previous studies have focused on the ability of cognitive symptom validity tests to identify simulated malingering or distinguish between clinical samples of individuals at low or high risk of cognitive symptom exaggeration. However, no published studies have examined the latent structure of negative response bias on cognitive tests: measures of cognitive symptom exaggeration may evaluate a continuum of poor effort/invalid responding or a dichotomy of adequate versus inadequate effort. The present study examined whether Victoria Symptom Validity Test (VSVT) indices evaluate a latent dimension or category of response distortion. The VSVT and personality data were obtained from 300 individuals who participated in neuropsychological evaluations as part of standard clinical care. Results indicated that VSVT accuracy scores measure a latent category of inadequate/adequate effort. Individuals classified as taxon members showed significantly poorer performance IQ and memory relative to individuals not classified as exhibiting distortion. The base rate of the identified cognitive symptom exaggeration taxon was estimated to be approximately .13-.14 in the present sample. Likelihood ratios are presented to assist clinical detection of individuals exhibiting the category of cognitive symptom exaggeration.