Examination of the relationship between symptom and performance validity measures across referral subtypes

Validation of PCL-5 symptom validity indices in a Cross-Cultural Forensic Sample

INTRODUCTION

Three symptom validity indices have recently been developed for the PTSD Checklist for DSM-5 (PCL-5). To date, these validity indices have been examined in North American research and clinical samples, generally with promising results. The current study aimed to cross-validate the symptom validity indices in a cross-cultural forensic sample.

METHOD

Examinees (N = 79) were Balkan (Macedonian, Kosovar, and Serbian) contractors previously employed at United States military bases in Afghanistan and Iraq. Examinees claimed posttraumatic stress disorder (PTSD) secondary to alleged adverse experiences, and they were pursuing Federal Workers' Compensation claims for PTSD under the auspices of the Defense Base Act. In this study, validity status was determined via outcome on the Inventory of Problems-29.

RESULTS

There were no significant differences between most demographic and background variables when groups were divided by validity status. Conversely, scores on all validity tests were significantly different between the group of examinees who were likely credibly presenting and the group that was likely noncredibly responding; medium to large effect sizes were observed. Area under the curve statistics ranged from .73 to .77. Sensitivity rates ranged from .33 to .47 when specificity was held at .90 or higher.

CONCLUSIONS

The findings converge well with prior research results, extending the use of PCL-5 symptom validity indices to a cross-cultural forensic sample.

Comparing the cognitive bias scale and cognitive bias scale of scales to other personality assessment inventory validity scales for detecting noncredible memory dysfunction in a clinical veteran sample

INTRODUCTION

The Cognitive Bias Scale (CBS) and the three Cognitive Bias Scale of Scales (CB-SOS) were developed for the Personality Assessment Inventory (PAI) to assess for cognitive response bias in neuropsychological settings and populations. While cross-validation research to date has been supportive, the scales have yet to be validated in a clinically referred veteran sample.

METHOD

Patients (N = 235) were clinically referred veterans who underwent neuropsychological evaluations. Individuals were classified into valid or invalid memory performance groups based on a criterion performance validity test. The CBS, the three CB-SOS, and multiple core and supplemental PAI symptom validity indices were examined.

RESULTS

Both the CBS and the three CB-SOS had large correlations with multiple over-report validity scales, and high concurrent elevation rates were observed across many of the over-report validity scales. The greatest area under the curve rates (i.e. .70 or above) were seen for the CBS, two of the CB-SOS, and one psychiatrically focused validity index. When maintaining specificity at ≥90%, the CBS and two of the CB-SOS demonstrated the best sensitivity rates (i.e. 28-29%).

CONCLUSIONS

While the CBS and the three CB-SOS have strong positive relationships with psychiatrically-focused over-report validity indices, the CBS and two of the CB-SOS demonstrated the best classification accuracy rates for identifying noncredible memory impairment. The cutoff scores and classification accuracy findings are in line with other published research results, suggesting good generalization to a clinically referred veteran sample. Additional conclusions regarding other findings are drawn and discussed.

A tale of two constructs: confirmatory factor analysis of performance and symptom validity tests

BACKGROUND

Performance validity (PV) and symptom validity (SV) tests assess biased responding that impact scores on neuropsychological tests. The extent to which PV and SV represent overlapping or unique constructs remains incompletely defined, especially among psychiatric patients in a non-forensic setting. The current study investigated this question using confirmatory factor analysis.

METHOD

Eighty-two inpatients with mood disorders were administered the Word Memory Test, and its primary indices formed a latent variable of PV. From the Minnesota Multiphasic Personality Inventory-2 the Fake Bad Scale (FBS), Response Bias Scale (RBS), and Henry-Heilbronner Index (HHI) were employed as a latent SV variable. Two models of the relationship between PV and SV were compared. One freely estimated the shared variance between SV and PV latent constructs. The other assumed the relationship between SV and PV was homogeneous, and covariance was fixed to 1.0.

RESULTS

In the freely estimated model, covariance between PV and SV was -0.18, and model fit was excellent (CFI = 0.098; TLI = 0.096; SRMR = 0.08). For the fixed model, the RBS, HHI, and FBS achieved low loadings on the SV construct, and model fit was poor (CFI = 0.66; TLI = 0.43; SRMR = 0.42).

CONCLUSIONS

PV as indexed by the WMT and SV measured by the MMPI-2 are not overlapping constructs among inpatients with mood disorders. These data imply that PV and SV represent distinct constructs in this population. Implications for practice are discussed.