Award Date

1-1-2008

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

First Committee Member

Daniel Allen

Number of Pages

164

Abstract

Individuals with severe mental illness report a higher incidence of trauma and PTSD than the general population. A trauma history in individuals with schizophrenia has been associated with more severe psychiatric symptoms including positive symptoms, depression, suicidality, anxiety, somatization and dissociation (Beck & van der Kolk, 1987; Craine, Henson, Colliver & MacLean, 1988; Ross, Anderson & Clark, 1994; Darves-Bornoz, & Gaillard, 1995; Holowka, King, Saheb, Pukall & Brunett, 2003; Strauss et al., 2006); The current study is among the first to examine the influence of comorbid schizophrenia and PTSD by performing comprehensive diagnostic, symptom and neurocognitive evaluations on four groups: normal controls (n = 26), a PTSD group (n = 21), a schizophrenia group (n = 26), and a group of individuals with schizophrenia and PTSD (n = 21); Participants were administered the Structured Clinical Interview for DSM-IV-TR Diagnosis (SCID). Those who met diagnostic criteria were administered a battery of tests designed to assess psychiatric symptoms (Schedule for the Assessment of Negative Symptoms, Schedule for the Assessment of Positive Symptoms, Brief Psychiatric Rating Scale, the Calgary Depression Rating Scale, and the Post-traumatic Stress Disorder Checklist-Civilian) and an extensive battery of neuropsychological tests in order to assess all major neurocognitive domains. It was hypothesized that the combined effects of schizophrenia and PTSD would produce greater neurocognitive impairment than either disorder when it occurred alone; Results of neurocognitive tests indicated that the schizophrenia groups performed significantly worse than the Control and PTSD groups in all neurocognitive domains. No significant differences were present between the PTSD and Control group. While the differences were not significant between the comorbid group (SZP) and the schizophrenia only group (SZ), there were some domains in which the mean performance of the SZP group was different than the means of the SZ group. The SZP group performed approximately one standard deviation poorer than the SZ group on the Attention Domain. Conversely, the SZP group scored approximately one-half of a standard deviation better than the SZ group on the Executive Domain and the Visual Learning/Memory Domain. Results of this study do not support the idea that the presence of comorbid PTSD results in increased cognitive impairment in schizophrenia, more than what might be expected in schizophrenia alone. In fact, the presence of PTSD in individuals with schizophrenia may be associated with slightly better performance in many neurocognitive domains. Results of this study do, however, suggest some areas of neurocognitive function to further investigate, including Attention, Executive Function, and Visual Memory. In conclusion, while the presence of PTSD in individuals with schizophrenia is associated with a different pattern of psychiatric symptoms, PTSD may not significantly impact neurocognitive function in a consistent manner, if at all.

Keywords

Associated; Attention; Comorbid; Executive Function; Impairment; Memory; Neurocognitive; Posttraumatic Stress Disorder; Schizophrenia

Controlled Subject

Clinical psychology; Cognitive psychology; Neurosciences

File Format

pdf

File Size

2.30 MB

Degree Grantor

University of Nevada, Las Vegas

Language

English

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