Award Date

August 2023

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Psychology

First Committee Member

Daniel Allen

Second Committee Member

Michelle G. Paul

Third Committee Member

Brenna Renn

Fourth Committee Member

Jennifer Keene

Number of Pages

131

Abstract

Approximately one-in-five individuals with psychotic disorders (i.e., schizophrenia spectrum disorders [SSD]) fail performance validity indicators (PVIs) during neurocognitive testing. Ensuring the validity of neurocognitive test results is necessary if the test scores are to be of use for diagnostic consideration, intervention selection and planning, predicting outcomes, and following changes in cognition over time in response to intervention, spontaneous recovery, or disease progression. PVIs are designed to require only a minimum level of engagement with the evaluation, which means nearly everyone is expected to “pass,” even those with moderate to severe brain damage. Traditional interpretations of PVI failure suggest a noncredible response style is likely motivated by secondary gain. However, the reasons for the increased failure rate among individuals with SSD are unclear but may be due to factors unrelated to a noncredible response style. Recent research suggests negative symptoms and cognitive deficits are associated with increased PVI failure rates, both of which are typically experienced by individuals with SSD. If failure on PVIs is not due to lack of engagement, then the usefulness of PVIs as indicators of noncredible performance in schizophrenia spectrum disorders may be questionable. Therefore, the current study investigated the validity of an emerging PVI (i.e., Reliable Spatial Span [RSS]) created from a well-validated cognitive test, as well as attempted to disentangle the associations with cognitive and symptom measures to determine whether cognitive deficits or symptomatic burden (i.e., negative and depressive symptoms) are more strongly associated with increased PVI performance in individuals with SSD. The current study used two samples: a training sample of individuals with SSD (n = 60) and a no diagnosis healthy control group (ND; n = 28) and a testing sample of individuals with SSD (n = 86) and ND (n = 129). The training sample was used to validate the RSS, establish diagnostic utility, and elucidate cognitive and symptomatology factors related to RSS performance. The testing sample was used to cross-validate findings and assess whether patterns of performance and relationships with RSS performance matched in an independent sample. Results established RSS as an acceptable measure of performance credibility, with excellent overall discrimination and sensitivity and specificity in range with other established embedded PVIs. Analysis of relationships with neurocognition and symptom severity factors revealed general neurocognition was significantly related to RSS performance, more so than specific neurocognitive domains of processing speed and learning and memory. In contrast, general neurocognition exhibited only a marginally stronger association with RSS performance compared to estimated IQ. No significant general patterns or relationships were identified between RSS performance and symptom severity measures. The absence of a significant relationship between negative symptoms and PVI failure suggests that factors other than negative symptomatology alone play a more prominent role in influencing performance credibility captured by PVIs. Possible explanations for this discrepancy include the direct impact of cognitive deficits on PVI performance, the limitations of the measures employed to assess negative symptoms, and the interplay between cognitive deficits and negative symptoms.

Keywords

dominance analysis (DA); effort tests; embedded validity tests (EVT); performance validity tests (PVT); receiver operating characteristic (ROC) analysis; schizoaffective disorder

Disciplines

Biological Psychology | Clinical Psychology | Mental and Social Health

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/


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