Psychology ETDs


Jessica Pommy

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Executive functioning (EF) impairments observed in schizophrenia (SZ) occur prior to onset of psychosis and are predictive of functional outcomes. There is significant variability in the nature and severity of EF deficits, however, and a better understanding of this heterogeneity could provide insight into the neurodevelopmental processes underlying both SZ and EFs. Using an approach similar to Fair et al., 2012, the present analysis examined heterogeneity in EFs and attempted to identify EF subtypes within healthy controls (HC) and individuals with SZ. EFs were assessed using the Trail Making Test, Verbal Fluency test, Tower of London, and Continuous Performance Test. A 4-factor model of EF (fluency, planning, shifting, attention) was tested in the sample using a Confirmatory Factor Analysis (CFA). The presence of EF subtypes was assessed separately in both groups using community detection (CD), an analytic technique based in graph theory that enables an unbiased analysis of community structure within complex networks. Results from the CFA supported a 4-factor model of EF. The CD analyses indicated greater modularity in SZ, and upon initial inspection, identified 7 EF subtypes in the SZ group that nested within 5 EF subtypes in the HC group. The impact of EF profiles on diagnostic accuracy was assessed using a machine learning approach. Results revealed improved diagnostic accuracy for a majority of the EF subtypes when EF profile was considered. Consistent with findings reported by Fair and colleagues, results support the existence of similar cognitive subtypes in the context of both normal and aberrant neurodevelopment.

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First Committee Member (Chair)

Thoma, Robert

Second Committee Member

Witkiewitz, Katie




Schizophrenia, executive function

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