Development of a validity scale for combat-related posttraumatic stress disorder: Evidence from simulated malingerers and actual disability claimants

Abstract

Individuals being evaluated for posttraumatic stress disorder (PTSD) in disability compensation cases or forensic settings are at increased risk of response bias, making the legitimacy of face-valid self-report measures assessing PTSD in these settings questionable. The following two studies evaluate the Quick Test for PTSD (Q-PTSD) as a time-efficient method of detecting response bias in individuals being assessed for combat-related PTSD. In the first study, 78 participants were randomly assigned to either an experimental group (simulated malingerers) or a control group (genuine reporting) and were administered the Q-PTSD along with a standard measure of combat-related PTSD. The Q-PTSD demonstrated suitable internal consistency and construct validity. Post-hoc analyses revealed that the best cutoff score for the Q-PTSD resulted in values ≥ .91 for sensitivity, specificity, positive predictive value, and negative predictive value in this sample. Utilizing the established cutoff, the second study evaluated the criterion-related validity of the Q-PTSD by assessing its correlation with the Morel Emotional Numbing Test for PTSD (MENT) in 67 military veterans applying for disability pensions and claiming combat-related PTSD.

Keywords:

• PTSD
• response bias
• MENT
• malingering
• assessment

Notes

1. The F-K scale is a derivative of the Infrequency (F) scale, high scores indicating deviant or atypical ways of responding, and the Correction (K) scale, low scores representative of examinees that exaggerate psychopathology and attempt to appear in a very unfavorable manner. Gough (1950) documented that high F minus K (F-K) scores were found in examinees attempting to create the false impression of severe psychopathology.

2. Due to proprietary rights and test security issues, the individual items on the Q-PTSD are not disclosed in this article. The official position of the National Academy of Neuropsychology (2002) regarding test security is that individuals ‘who gain access to test content can and do manipulate tests and coach others to manipulate results, and they are also more likely to circumvent methods for detecting test manipulation’ (p. 384; see also Bauer & McCaffrey, 2006; Ruiz, Drake, Glass, Marcotte, & van Gorp, 2002). Similarly, Conroy and Kwartner (2006) noted that ‘increased knowledge of detection techniques can enhance malingering skills’ (p. 44).

3. The experimental group and control group are dichotomous variables, and so these variables yield point-biserial correlations.

4. In all, 75 consecutive compensation and pension assessments for PTSD were reviewed but eight cases were not included in the analysis because the claimants were also being evaluated for neuropsychological dysfunction.

5. A task force on PTSD at the Veterans Affairs Medical Center had previously approved a standard test battery for compensation evaluations of PTSD, which included the MSS, the Combat Exposure Scale, the MMPI-2, the MENT, and the questions from the Q-PTSD.