ABSTRACT
This chapter introduces some basic facts about sleep and how it is regulated in healthy adults. Sleep is a state characterised by changes in brainwave activity, breathing, heart rate, body temperature, and several other physiological functions. Sleep architecture refers to the way that sleep is structured across the night. In many psychiatric disorders, including psychotic disorders, there are characteristic changes in sleep architecture compared with that of healthy people. Sound sleep is facilitated by a strong sleep drive and a sleep–wake schedule that is congruent with the body clock. For good sleepers, the wind-down period before bed and the bedroom itself are associated with feeling relaxed and sleepy. When sleep is disrupted for a period of time, however, there is ample opportunity for the pre-sleep period or the bedroom to become associated with feeling alert and awake.
