Understanding and Exploring the Factors and Interventions Associated with Psychosis

Literature Review: Previous research has found clear evidence to support the effectiveness of self-help interventions in improving psychotic outcomes. However, little is known about the effectiveness of cognitive behavioural therapy (CBT) specific self-help for psychosis, given that CBT is a highly recommended treatment for psychosis. Over recent years, research has grown regarding CBT-specific self-help for psychosis, warranting an overall review of the literature. The first section of this thesis aimed to review the literature base on CBT-based self-help interventions in treating psychosis and other related outcomes. Moreover, this review aimed to gain insight into the forms of CBT-based self-help that have been developed over time, given that a substantive review of this has not been completed. Of the 10 included studies, seven papers found credible evidence to support the effectiveness and efficacy in reducing psychotic symptoms post-intervention. Some evidence was also found for improving secondary outcomes to psychosis, such as anxiety and depressive symptoms, as well as improving daily functioning skills and overall well-being. The review was the first to solely explore the effectiveness of CBT-based self-help for psychosis as well as associated outcomes. Due to some reported methodological limitations and concerns with study quality, the findings should be interpreted with some caution. Further studies of higher quality, exploring effectiveness with included follow-up periods, is required to understand effectiveness longevity. Empirical Study: The second part of the thesis reports an empirical study, which aimed to explore factors relating to hallucination tendencies, building on past research. Previous studies have shown that people with psychosis have abnormal source monitoring skills (usually measured with a signal detection task), and hence an impaired ability to know whether a voice is present or not; it is also known that early childhood trauma is a risk factor for hallucinations, but trauma does not seem to be associated with impaired source monitoring (Varese et al.,2012). People with PTSD who, like people with psychosis have extensive trauma histories, but do not typically experience hallucinations, were therefore expected to differ from people with hallucinations by having preserved source monitoring. Hence, the authors predicted that, in a comparison between people with PTSD and people with psychosis, source monitoring abnormalities would be specific to people with psychosis. An online cross-sectional between-groups study was conducted. Three groups (PTSD, psychosis, healthy controls) of participants (N = 81) completed a battery of outcome measures on trauma, dissociation, and voice hearing. Participants also completed an online signal detection task to measure source monitoring ability. It was found that the psychosis sample had abnormal bias scores on the source monitoring task, evidencing more bias to assume a voice was present under uncertain conditions. The results found no direct link between childhood trauma and source monitoring ability, suggesting that source monitoring is a possible neurocognitive deficit unique to people with psychosis. Future studies should research the neurocognitive basis of source monitoring deficits in psychosis, and potential future interventions to improve source monitoring skills. Clinical implications, strengths and limitations of the research and described in the report.