Sleep at night and patients’ behaviours the next day in a catchment-area-based psychiatric hospital

Abstract

This thesis explores the associations between sleep at night and behaviour the next day in two patient samples from a defined catchment area admitted to the Department of Psychiatry, St Olav’s University Hospital: outpatients with delayed sleep-wake phase disorder (DSWPD) admitted to the specialist clinic for patients with sleep disorders, and inpatients acutely admitted to the psychiatric intensive care units (PICUs). Sleep is an essential function for all animals, including humans. Disruption of sleep patterns and lack of sleep affect our functioning and behaviour. Lack of sleep has numerous effects, ranging from deterioration in performance on more complicated cognitive tasks to being associated to a number of somatic health problems, such as increased weight, diabetes, and decreased life expectancy. The associations between sleep and daytime functioning are complex and bidirectional. Among outpatients with DSWPD and acute psychiatric inpatients admitted to PICUs, disturbed sleep and challenging behaviour is common. The impact of sleep disruptions on behaviour the next day is seldom studied. This thesis aimed to study the awakening threshold and changes in cognitive function after awakening in DSWPD patients. Additionally to study the effects of sleep duration or night-tonight variations in sleep duration on length of stay and observer-rated aggressive behaviours in acutely admitted psychiatric patients, and finally to investigate whether the predictive properties of a violence risk instrument predicted aggressive incidents more precisely if a sleep variable was added to it. Methods Paper one reports data from nine patients with DSWPD and nine sex- and age-matched healthy controls who stayed in the sleep laboratory for one night. They were examined with polysomnography and completed the continuous performance test (CPT) in the afternoon and immediately upon waking. An alarm clock was activated at 07:00 with sound intensity increasing from 72 to 104 dB. Paper two reports data from 135 patients consecutively admitted to a PICU. Papers three and four report data for 50 of these admissions. The nurses registered the time the patients were sleeping, aggressive behaviours using the Brøset Violence Checklist (BVC), and aggressive incidents using the Staff Observation Aggression Scale-Revised (SOAS-R). Results In all patient groups we found wide variability in sleep duration between individuals. Three of the patients with DSWPD did not wake up at the alarm sound of 104 dB. The three patients were in rapid eye movement (REM) sleep. On the CPT test, patients with DSWPD had longer reaction times in the morning than in the afternoon. In the acutely admitted subgroup of patients with schizophrenia, sleep duration the first night correlated negatively with the length of stay. For the whole group of patients, the difference in sleep duration from night one to night two were correlated with length of stay. Short sleep duration the first night correlated with aggressive behaviour the next day. During the stay, large absolute differences in sleep duration between two consecutive nights correlated withaggressive behaviour the next day, and short sleep duration was associated with violent incidents. The violence risk instrument BVC appeared to predict aggressive incidents more precisely when a sleep variable was added. Discussion We found that patients with DSWPD struggle to wake up with an alarm clock. These patients were in a period of REM sleep, rather than in the expected period of slow wave sleep (SWS). Their reported drowsiness in the morning was supported by a neuropsychological test. Among the acute psychiatric patients in the PICUs, we found large variations in sleep duration between individual patients, as well as large intra-individual lack of stability in sleep duration. The lack of stability in sleep duration, and the magnitude of the night-to-night variations of the first nights predicted the length of stay in the PICU. These factors were also associated with threatening behaviour and aggressive incidents. Assessments of sleep disorders may increase the value of psychometric instruments designed to predict the imminent risk of violence in psychiatric inpatients. The studies had a limited number of participants. There were also limitations in the designs and measures used. Thus, the results should be interpreted with caution. The two-process model theory of sleep regulation may be useful when comparing studies, interpreting results and seeking new treatments