The first chapter consists of a systematic literature review, which asks the research question: what does the literature to date tell us about schemas in psychosis and at-risk populations? A systematic search identified a total of 23 studies that met the inclusion criteria. Negative schema were elevated across the continuum of clinical psychotic groups, but were not characteristic of non-clinical samples having psychotic like experiences. Associations were found between schemas and a range of psychotic symptomology in clinical groups. There was preliminary evidence suggesting schemas may partially mediate the relationship between trauma and psychotic symptoms, lending support to cognitive models of psychosis. One intervention study showed the potential benefits of targeting underlying self-schema. Firm conclusions cannot be drawn at this time as the majority of studies employed a cross-sectional design.
The second chapter examines the empirical research investigating associations between schemas and beliefs about voices, and the relationship between the hearer and their voice. A total of 44 voice-hearing participants completed questionnaires assessing schemas, beliefs about voices, and the perceived relationship with their voice. A clinician rating scale assessed different dimensions of their voice-hearing experience. Beliefs about voices correlated with negative voice content and schemas. After controlling for negative voice content, schemas were estimated to predict 1-17% of the variance in the six beliefs about voices; three of the associations reached statistical significance. Schemas also correlated with dimensions of relating between the hearer and their voice. This study provides evidence that schemas may be important when considering beliefs about voices and the perceived relationship between the hearer and their voice.
The third chapter discusses the implications for theory development, clinical practice, and future research, arising from the first two papers. A reflective commentary is provided at the close of the thesis.