A longitudinal high-resolution exploration into the relationship between sleep disruption and ‘in vivo’ psychotic symptoms, paranoia, and dissociation in early phase psychosis.

More than a century of research highlights the omnipresence of sleep and circadian rhythm disruption in psychosis. While earlier understandings focused more on this being a consequence or ‘side effect’ of psychosis, emergent research has highlighted the potential for a causal pathophysiological link. Clarifying this relationship could pave the way for more targeted treatment programs in early phase psychosis. This thesis opens with a comprehensive overview of the literature surrounding sleep, circadian rhythms, and psychosis to date (Part 1). This overview closes by highlighting that the nature of the relationship (i.e. which specific psychotic experiences (PE) and sleep or circadian parameters are related), directionality of the relationship and whether there is convincing evidence to infer causality remains unclear. Experimental and clinical studies in both clinical and analogue populations have provided mixed results. This highlights the need for more mechanism-driven research targeting specific experiences within psychosis. An empirical study follows in Part 2. This study uses experience sampling method in tandem with actigraphy which permits high resolution sampling of daily “in vivo” psychotic experiences with nightly subjective and objective sleep metrics. This is study was designed to address some of the caveats described in Part 1 and takes a mechanism-driven approach to exploring whether nightly sleep or circadian rhythmicity is predictive of next day hallucinations, dissociation, and paranoia in early phase psychosis. In Part 3, this thesis closes with a critical reflection of the work and what I as a researcher have learned through the process of this study and will take forward into both my clinical and academic career