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This electronic thesis or dissertation has been downloaded from the King’s Research Portal at https://kclpure.kcl.ac.uk/portal/ What are the psychological factors that may mediate the relationship between childhood trauma and later positive symptoms of psychosis? Doris, Emma Elizabeth Awarding institution: King's College London The copyright of this thesis rests with the author and no quotation from it or information derived from it may be published without proper acknowledgement. END USER LICENCE AGREEMENT Unless another licence is stated on the immediately following page this work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International licence. https://creativecommons.org/licenses/by-nc-nd/4.0/ You are free to copy, distribute and transmit the work Under the following conditions: Attribution: You must attribute the work in the manner specified by the author (but not in any way that suggests that they endorse you or your use of the work). 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Sep. 2021 Volume I Systematic Review Empirical Research Project Service Evaluation Project Thesis submitted in partial fulfilment for the degree of Doctorate in Clinical Psychology ____________________________________________________________ Emma Doris Institute of Psychiatry King’s College London May 2015 1 Acknowledgments Firstly, I would like to thank all the participants who took part in the study for their time and effort; this study would not have been possible without them. I would like to thank my supervisors, Dr Elaine Hunter, Dr Amy Hardy and Dr Emmanuelle Peters, for their help, support and encouragement over the past few years. I have learnt from you all enormously and I’m grateful for all the guidance and knowledge you have given me. Thank you for patience, commitment and generosity with your time. I would also like to thank Charlotte Sykes for making joint working an enjoyable experience and for your support during data collection. Finally, I thank my friends and family for their continuing love, encouragement and understanding. 2 Overview of contents Systematic Review What are the psychological factors that may mediate the relationship between childhood trauma and later positive symptoms of psychosis? Page 4 _____________________________________________ Empirical Research Project What is the role of dissociative processes in the relationship between childhood trauma and psychosis? Page 51 _____________________________________________ Service Evaluation Project Pilot of a new opt-in system in an IAPT service Page 142 _____________________________________________ 3 Systematic Review ____________________________________________________________ What are the psychological factors that may mediate the relationship between childhood trauma and later positive symptoms of psychosis? Supervised by Dr Emmanuelle Peters, Dr Elaine Hunter & Dr Amy Hardy 4 Abstract Aims: Childhood trauma (CT) is increasingly recognised as a potential risk factor for the development of positive symptoms of psychosis. As a result, studies are beginning to investigate potential psychological factors that may mediate this relationship. This review sought to identify, summarise and critically evaluate studies that investigated psychological factors as mediating processes between CT and positive symptoms in people with psychosis. Method: The following computerised databases were searched up to March 2015; ISI Web of Science, PsychInfo and Pubmed. These were supplemented with manual searches. After screening, papers relevant to the review question were examined in more detail and quality assessment ratings were completed. Results: A total of 44 papers were identified comprising 10,161 participants. Two papers examined anomalous experiences, 2 attachment, 2 theory of mind (ToM), 9 neurocognitive functioning, 7 post-traumatic stress disorder (PTSD) and 22 dissociation. Quality varied across studies and some frequent methodological limitations were identified. Conclusion: There is some evidence to support a mediating role of dissociative experiences and attachment anxiety in the relationship between CT and positive symptoms. It is not possible to draw conclusions concerning the other factors under review. Future research should aim to address methodological limitations of existing studies and should consider multiple factors within a single sample. 5 Table of contents 1 Introduction ………………………………………………………………………………………………………… 7 1.1 Childhood trauma and psychosis………………………………………………………….. 7 1.2 Potential mediating factors………………………………………………………………….. 8 2 Method………………………………………………………………………………………………………………… 10 2.1 Literature Search………………………………………………………………………………….. 10 2.1.1 Inclusion/exclusion criteria …………………………………………… 10 2.1.2 Search Strategy……………………………………………………………...10 2.2 Assessment of quality…………………………………………………………………………… 10 2.3 Data extraction…………………………………………………………………………………….. 11 3 Results……………………………………………………………………………………………………………….... 13 3.1 Study characteristics ……………………………………………………………………………..13 3.2 Methodological quality of reviewed studies ………………………………………… 30 3.3 Findings of reviewed studies ……………………………………………………………….. 33 3.3.1 Anomalous experiences ……………………………………………….. 33 3.3.2 Attachment…………………………………………………………………… 33 3.3.3 Theory of mind……………………………………………………………… 34 3.3.4 Neurocognitive functioning………………………………………….. 34 3.3.5 PTSD……………………………………………………………………………… 35 3.3.6 Dissociation…………………………………………………………………… 36 3.3.6.1 Childhood trauma and dissociation 36 3.3.6.2 Dissociation and positive symptoms 37 3.3.6.3 Dissociation as a mediating factor 38 4 Discussion…………………………………………………………………………………………………………….. 38 4.1 Methodological limitations…………………………………………………………………… 39 4.2 Study limitations………………………………………………………………………………….. 40 4.3 Research implications…………………………………………………………………………… 41 4.4 Clinical implications……………………………………………………………………………….42 4.5 Conclusion……………………………………………………………………………………………. 42 References………………………………………………………………………………………………………………………..43 List of Figures Figure 1: Flowchart of article selection process……………………………………………………………… 14 List of Tables Table 1: Search terms for potential mediating factors examined …………………………………… 11 Table 2: Quality rating scale…………………………………………………………………………………………….. 12 Table 3: Characteristics of studies included in the systematic review……………………………… 16 Table 4: Quality scores of reviewed studies…………………………………………………………………….. 31 6 1 Introduction 1.1 Childhood trauma and psychosis A significant proportion of individuals with psychosis1 report adverse childhood experiences, such as emotional and physical abuse. Recent meta-analyses have confirmed a significant relationship between childhood trauma (CT) and positive symptoms in adulthood (Matheson, Shepherd, Pinchbeck, Laurens, & Carr 2013; Varese et al., 2012a). The first of these calculated that those with psychosis were 2.72 times more likely to have been exposed to CT than controls (Varese et al., 2012a). Similarly, the more recent meta-analysis found a medium to large effect of childhood adversity in people with schizophrenia (Matheson et al., 2013). Whilst some have argued that the association between CT and psychosis has been overstated (e.g. Susser & Widom, 2012), others have begun to consider the psychological mechanisms by which these factors may be related. Several psychological models have been proposed to explain how trauma may influence the development and maintenance of psychotic experiences which focus on the causal role of CT in the development of positive symptoms (e.g. Read, Perry, Moskowitz, & Connolly, 2001). A cognitive-behavioural model of psychosis suggests that emotional changes, for example in response to trauma, may give rise to alterations in sensory perceptual experience, appraisals of which may lead to positive symptoms (Garety, Kuipers, Fowler, Freeman, & Bebbington, 2001). Another model proposes that trauma in the context of psycho-social vulnerabilities leads to intrusions which, in combination with dissociative experiences, may then be appraised in culturally unacceptable ways, leading to psychosis (Morrison, Frame, & Larkin, 2003). A compassion-focused model of psychosis suggests that CT may lead to disorganised attachment and emotion regulation difficulties, one consequence of which is increased tendency towards dissociation (Gumley, Braehler, Laithwaite, MacBeth, & Gilbert, 2010). The catastrophic interaction hypothesis proposes that an interaction between difficulties integrating sensory perceptual experiences due to problems with contextual integration (Steel, Fowler, & Holmes, 2005) and emotional reactions to stress or trauma results in vulnerability to intrusive experiences that contribute to hallucinations and delusional beliefs (Fowler et al., 2006). It is clear from these models that there are multiple psychological factors through which CT may be hypothesised to influence the development and maintenance of positive symptoms. 1 The term ‘psychosis’ rather than ‘schizophrenia’ is used here as it is the spectrum of phenomena, rather than a specific diagnostic