Effectively Assessing Sleep and Circadian Rhythms in Psychosis

Abstract This chapter is designed to provide a comprehensive overview of the regulation of sleep and circadian rhythms so that readers are well equipped to assess a broad number of sleep and circadian rhythm disruptions (SCRD). Whilst often not given a lot of attention in clinical or neuropsychology training, SCRD transcend numerous diagnostic boundaries and have grave implications for functioning, coping and prognosis, and should thus form an essential part of any assessment in psychosis. The aims of this chapter are to inform basic understanding of sleep and circadian rhythm biology (including a brief synopsis on the two-process model, the biological clock in the brain, and individual differences in sleep timing), before examining what disruption to this process can involve. Given that people with psychosis often have many coexisting problems (e.g. depression, anxiety, posttraumatic stress disorder), this chapter provides a brief overview of SCRD across the diagnostic spectrum before focusing on the most commonly found SCRD in psychosis. This should give readers a deeper understanding of the neurobiology underpinning SCRD, how SCRD manifests in people with psychosis, and the optimal assessment options to grapple with SCRD.