P029 Sleep and circadian rhythm disturbances and relapse in schizophrenia: a digital phenotyping study

Introduction Disturbances in sleep and circadian rhythm (SCR) are frequently reported prior to and during episodes of relapse in schizophrenia, and may serve as an early marker of deterioration. However, this has never been demonstrated objectively. Novel approaches using mobile technologies are enabling the longitudinal sampling of sleep-circadian rhythms in the real-world. In this preliminary descriptive analysis, we asked whether SCR disruption captured by a remote-monitoring system accompanies symptomatic deterioration in schizophrenia. Methods The Sleepsight study gathered light, geolocation, phone interaction and physical activity parameters from wearable and smartphone sensor-streams, passively, continuously, remotely and in real-time over 12 months, in 36 individuals with schizophrenia. Fluctuations in clinical status were also sampled via a daily smartphone sleep and symptom diary, and relapse events were determined through clinical record review. Results 15 episodes of relapse were identified over the study period, in 12 individuals. Reduction in mean sleep duration was observed to accompany deterioration in 10 episodes, and preceded the onset of significant disturbance of mental state in six of these cases. The longitudinal mean sleep duration for one participant who experienced three relapse episodes over the study period is illustrated in figure 1. Markedly disrupted circadian rhythms including free-running rhythms and relative coordination with weak entrainment were observed in three participants, and were associated with poorer outcomes. Discussion Sleep and circadian rhythm disturbances commonly accompany relapse in schizophrenia, and emerges prior to deterioration in over half of cases. Sleep-circadian dysregulation may therefore be implicated in the pathophysiology of relapse, and serve as a predictive marker of impending deterioration.