Dissertations, Theses, and Capstone Projects

Date of Degree

9-2022

Document Type

Dissertation

Degree Name

Ph.D.

Program

Psychology

Advisor

Deborah J. Walder

Committee Members

Veronica Hinton

Anthony Ahmed

Yvette Caro

Justin Storbeck

Subject Categories

Clinical Psychology

Keywords

schizotypy, schizophrenia, aberrant salience, self-disorder, basic self-disturbance

Abstract

Within this investigation, the self-disorder hypothesis of schizophrenia was assessed via an illusory perceptual paradigm. It has been proposed that alteration of basic (minimal) selfhood may underlie cognitive and perceptual disturbances in psychosis (Sass, 2014). Disturbed corporeality (i.e., anomalous experience of one’s body) is an identified component of basic self-disturbance. As it is difficult to empirically capture the spontaneous occurrence of anomalous bodily experiences as they arise, the Pinocchio Illusion (PI) has been employed to capture variations in the plasticity of bodily self-experience (specifically, body boundary plasticity) (Michael & Park, 2016). The PI paradigm provides for the sensations of arm elongation and nose growth. The present study utilized the PI paradigm to examine variability in the plasticity of body boundaries in relation to schizotypy in a non-clinical sample of undergraduate students in an urban setting. Specifically, prediction of schizotypy by body boundary plasticity (via the PI) was examined. As anomalous experience of the body is but one of several features of basic self-disturbance, a broader capturing of anomalous self-experiences was attained through utilization of the Inventory of Psychotic-Like Anomalous Self-Experiences (IPASE) (Cicero et al., 2017). The prediction of schizotypy by endorsed anomalous self-experiences was assessed. Additionally, aberrant salience has been proposed to be a neurocognitive correlate of basic self-disturbance (Nelson, Whitford, Lavoie, et al., 2013). Thus, this study also examined the relationship between trait aberrant salience (using the Aberrant Salience Inventory; ASI) and anomalous bodily experiences using both the PI paradigm and the Perceptual Aberration Scale (PAS; a self-report measure employed for the initial assessment of body-based self-disturbance) (Cicero, Kerns, & McCarthy, 2010; Chapman, Chapman, & Raulin, 1978). The relationship between trait aberrant salience and IPASE scores was also assessed. Potential modulation by trait aberrant salience of the predictive relationship between anomalous self-experiences (including aberrant experiences of one’s body) and schizotypy was examined. Lastly, greater experience of body-based aberrations has been associated with reduced ability to accurately discern among tactile inputs in clinical populations (Michael & Park, 2016). In turn, tactile discriminability (using the Two-Point Discrimination Task; 2-PT) was examined in relation to body-based aberrations and schizotypy (Chang & Lenzenweger, 2005). Study results from multiple linear regression models evidenced the significant prediction of schizotypy by basic self-disturbance (i.e., via measures of anomalous self and bodily experiences). Additionally, these individual predictive relationships were, either partially or fully, mediated by trait aberrant salience. Further, anomalous bodily experiences were not significantly associated with reduced tactile discriminability. Findings contribute to our understanding of the role of basic self-disturbance in psychosis risk and provide novel support of the modulation of relationships among measures of basic self-disturbance and schizotypy by trait aberrant salience. Clinical implications include the potential to inform the utility of including basic self-disturbance assessment in psychosis risk evaluations, with the goal of increasing precision of early risk identification. In turn, results may also inform future development of preventive and early intervention strategies.

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