Sleep and psychosis

This chapter provides a brief overview of sleep and its link with psychosis. The chapter is organized into three main sections. First, we provide a brief introduction into the fundamentals of sleep and discuss its measurement, the classification of sleep states and their architecture, and the regulation of the rhythm of wakefulness and sleep. This is followed by an overview of the association between sleep disorders (namely, insomnia, nightmare disorder, circadian rhythm sleep-wake disorder, and narcolepsy) and psychosis, and we also discuss reported alterations of sleep electroencephalography (EEG) patterns in patients with schizophrenia. The last section of the chapter proposes some cognitive constructs that could mediate the association between disturbed sleep and psychosis. We present evidence suggesting that sleep disturbances could induce psychosis by reducing prepulse inhibition, impairing reasoning and cognitive flexibility, disrupting source monitoring errors, and/or increasing proneness to false memories. We conclude the chapter by highlighting some of the outstanding questions on the link between sleep and psychosis.