Investigating Causal Beliefs in People Experiencing Psychosis

  • Lucy Carter

Student thesis: Phd


This thesis explored the impact of causal beliefs on treatment outcome and stigma in people who have experience of psychosis. A multi-method approach was utilised. Chapter 1 provides a background to the thesis and an overview of current findings and this is followed by a review of the methodologies in Chapter 2. Study one (Chapter 3) provides a systematic review and narrative of current research on this topic. This identified a distinct lack of research within this area of study and highlighted mixed findings in relation to the importance of causal beliefs on treatment outcome. Study two (Chapter 4) used qualitative interviews to examine factors that influenced the development and maintenance of causal beliefs using a thematic approach. This identified a number of themes, including the role of information processing and affect. Study three (Chapter 5) explored the opinions about the cause of psychosis in a group of clinicians and the relationship between these beliefs and opinions about the helpfulness of treatment. Clinicians who endorsed psychosocial causes viewed CBT as more helpful, whilst clinicians with biogenetic beliefs were more likely to believe medication would be helpful. Study four (Chapter six) explored the causal beliefs of a large group of service-users and how these beliefs were related to perceptions about the helpfulness of treatment and the treatment accessed. This study found that service-users endorsed a number of different causes but preferred a psychosocial model overall. Only a small number of significant relationships between beliefs and treatment were identified. Study five (Chapter 7) utilised an experimental design to examine the impact of two explanatory models (biogenetic vs. psychosocial) on internalised and external stigma in people experiencing psychosis. Results indicated a significant reduction in internalised stigma in both groups. Only those in the psychosocial group observed a reduction of external stigma. Study six (chapter 8) explored the relationship between causal beliefs and different aspects of treatment (perceptions, adherence, outcome) with individuals participating in an RCT. Psychosocial beliefs were associated with a belief that therapy would be helpful, whilst biogenetic beliefs were associated with a belief that medication would be helpful. No relationships were identified between beliefs and adherence with medication or engagement with therapy or treatment outcome. This thesis has provided an overview of current causal beliefs in a large group of service-users and clinicians. These suggest that both groups endorse a multi-factorial model, but prefer psychosocial explanations. Some relationships were found between beliefs and treatment, in particularly in relation to opinions about the helpfulness of treatment. This suggests that beliefs may influence attitudes in a meaningful way. However, beliefs were found not to influence treatment adherence, engagement or perceptions about the helpfulness of different treatment options. Finally, the experimental study identified some interesting relationships between beliefs and the different domains of stigma, suggesting that aetiological information influences internalised stigma and external stigma differentially. The clinical and research implications of this are discussed.
Date of Award31 Dec 2017
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorAnthony Morrison (Supervisor) & Melissa Pyle (Supervisor)


  • Causal beliefs
  • Psychosis

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