[Truncated abstract] Auditory hallucinations (AHs) are one of the most common symptoms of schizophrenia, and are associated with high levels of distress, functional impairment, and need for care. However, current understanding of the exact causes and thus treatment of AHs is still in its infancy. Recently, Badcock and colleagues proposed a cognitive dual-deficit model of AHs, which stipulates that intentional inhibition deficits underlie the intrusive and unintentional nature of AHs, while context memory binding deficits explain the source misattribution (Waters, Badcock, Michie, & Maybery, 2006). While this model seems to best explain the different features of AHs, the precise components of inhibitory control involved, and the evident role of negative affect in the production of AHs, have not been empirically examined. Thus, the first two aims of this thesis were to clarify the critical component(s) of inhibitory control specifically related to AHs, and to examine the relationships between negative affect (chiefly anxiety), AHs and inhibitory control. Finally, AHs are also commonly reported by individuals in the general population, consistent with a continuum approach to AHs. Accordingly, the third aim of this thesis was to investigate whether similar relationships exist between hallucinatory-type experiences, inhibitory processes and negative affect in both hallucination predisposition and schizophrenia. The first study presents the findings from two related investigations of hallucination predisposition. ... However, the study revealed a significant relationship between intentional inhibition and trait anxiety (which was independent of hallucination predisposition) allowing the possibility that more severe or longer lasting changes in anxiety may indeed exacerbate difficulties with intentional inhibition. The final study sought to determine whether the pattern of relationships between AHs, inhibitory impairments and anxiety in schizophrenia are similar to those found in hallucination predisposition. The same three cognitive tasks previously employed (ICIM, B-P, and DI) were administered to schizophrenia (N = 61) and healthy control (N = 34) participants. Schizophrenia participants overall exhibited difficulties intentionally resisting interference from distracting stimuli, however did not have difficulties [intentionally or unintentionally] inhibiting task-irrelevant memory traces. Consistent with the continuum approach, AHs were related only to difficulties with intentional inhibition, and these difficulties existed independently from anxiety (although anxiety was related to intentional inhibition) and were unrelated to other schizophrenia symptoms. Together, the studies support the first component of Badcock et al.'s dual-deficit model of AHs, with hallucinatory experiences in both hallucination predisposition and schizophrenia associated with specific intentional inhibition impairments. The findings also suggest that while anxiety may contribute to the production of AHs by exacerbating v existing intentional inhibition impairments, it is likely that anxiety has additional routes of influence. These findings provide strong support for the continuum approach to AHs. The implications of these findings and possible avenues for future research are discussed.
| Identifer | oai:union.ndltd.org:ADTP/194824 |
| Date | January 1900 |
| Creators | Paulik, Georgina |
| Publisher | University of Western Australia. |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | Copyright Georgina Paulik, http://www.itpo.uwa.edu.au/UWA-Computer-And-Software-Use-Regulations.html |
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