AbstractSleep disturbance is a prevalent complaint amongst individuals with a diagnosis of schizophrenia. However, very little research has explored the effects of sleep difficulties on the experience of psychotic symptoms and functioning. Therefore, this thesis provides a detailed examination of the role of sleep disturbance in people with a diagnosis of schizophrenia. It is presented in three papers: (1) a systematic review; (2) an empirical study and (3) a critical evaluation and reflection on the research process. Paper one presents a systematic review of the relationship between objective and subjective sleep disturbance and psychosis severity, within the context of schizophrenia-spectrum diagnoses. Twenty six papers were identified through electronic database searches and reference list searches of relevant articles and reviews. All papers met pre-defined inclusion and exclusion criteria. Both objective and subjective sleep disturbance was associated with increased psychosis severity; however, evidence was weak-to-moderate in quality as few studies controlled for confounders. Recommendations for future research were suggested to improve the quality of prospective studies aiming to elucidate the sleep-psychosis relationship.Paper two presents the first, well-controlled, longitudinal examination of the relationship between objective and subjective sleep parameters, next-day psychotic symptoms and functioning. Objective and subjective sleep parameters were assessed across six days and nights of actigraphy and completion of morning sleep diaries. Using Experience Sampling Methodology (ESM), assessments of mood, psychotic symptoms and functioning were completed five times each day, by twenty-two participants with a schizophrenia-spectrum diagnosis. All objective and subjective sleep parameters predicted impaired next-day functioning, which remained significant after controlling for symptom severity. Reduced sleep efficiency and increased sleep fragmentation predicted next-day auditory hallucinations, while increased sleep fragmentation and reduced sleep quality predicted next-day paranoia and delusions of control. A proportion of all significant relationships between sleep and next-day variables were mediated by morning negative affect.Paper three describes a critical evaluation and reflection of the research process. This includes reflections on key methodological decisions and their underlying rationale, personal reflections on the completion of papers one and two and discussion of the overall findings within the context of clinical practice. Paper three concludes that sleep disturbance appears related to symptom severity and impaired functioning in people with a diagnosis of schizophrenia. Sleep could therefore represent a key target for therapeutic intervention, which has the potential to enhance both symptomatic and functional recovery.
|Date of Award
|31 Dec 2015
|Gillian Haddock (Supervisor) & Simon Kyle (Supervisor)