High resolution examination of the role of sleep disturbance in predicting functioning and psychotic symptoms in schizophrenia: A novel experience sampling study

Sleep disturbance is common in schizophrenia, but its role in predicting functioning and psychotic symptoms has yet to be rigorously examined. The purpose of this study was to conduct a prospective, high-resolution examination of the relationship between nightly sleep and next-day functioning and psychotic symptoms in people with a diagnosis of schizophrenia. Experience sampling methodology was integrated with actigraphy and sleep diaries across 7 days in 22 patients with a diagnosis of schizophrenia. Momentary assessments of mood, psychotic symptoms, and functioning were gathered at 5 points each day following pseudorandom schedules. Multilevel modeling was performed to evaluate the links between variables. Objective and subjective sleep disturbance predicted reduced next-day functioning, which remained significant after controlling for psychotic symptom severity. Increased sleep fragmentation and reduced subjective and objective sleep efficiency predicted greater next-day auditory hallucinations, whereas increased objective sleep fragmentation and reduced subjective sleep quality predicted greater paranoia and delusions of control. Negative affect on awakening mediated a proportion of these relationships (range: 17.9–57.3%). For the first time, we show that sleep disturbance is a predictor of next-day impaired functioning and psychotic symptom severity in people with a diagnosis of schizophrenia. Therefore, interventions targeting sleep may have the potential to directly and indirectly enhance functional and symptomatic recovery in those experiencing psychosis.