Obstructive sleep apnoea and schizophrenia: a primer for psychiatrists

Metabotropic glutamate receptor function and regulation of sleep-wake cycles

Metabotropic glutamate (mGlu) receptors are the most abundant family of G-protein coupled receptors and are widely expressed throughout the central nervous system (CNS). Alterations in glutamate homeostasis, including dysregulations in mGlu receptor function, have been indicated as key contributors to multiple CNS disorders. Fluctuations in mGlu receptor expression and function also occur across diurnal sleep-wake cycles. Sleep disturbances including insomnia are frequently comorbid with neuropsychiatric, neurodevelopmental, and neurodegenerative conditions. These often precede behavioral symptoms and/or correlate with symptom severity and relapse. Chronic sleep disturbances may also be a consequence of primary symptom progression and can exacerbate neurodegeneration in disorders including Alzheimer's disease (AD). Thus, there is a bidirectional relationship between sleep disturbances and CNS disorders; disrupted sleep may serve as both a cause and a consequence of the disorder. Importantly, comorbid sleep disturbances are rarely a direct target of primary pharmacological treatments for neuropsychiatric disorders even though improving sleep can positively impact other symptom clusters. This chapter details known roles of mGlu receptor subtypes in both sleep-wake regulation and CNS disorders focusing on schizophrenia, major depressive disorder, post-traumatic stress disorder, AD, and substance use disorder (cocaine and opioid). In this chapter, preclinical electrophysiological, genetic, and pharmacological studies are described, and, when possible, human genetic, imaging, and post-mortem studies are also discussed. In addition to reviewing the important relationships between sleep, mGlu receptors, and CNS disorders, this chapter highlights the development of selective mGlu receptor ligands that hold promise for improving both primary symptoms and sleep disturbances.

Self-reported suboptimal sleep and receipt of sleep assessment and treatment among persons with and without a mental health condition in Australia: a cross sectional study

BACKGROUND

Poor sleep and poor mental health go hand in hand and, together, can have an adverse impact on physical health. Given the already disproportionate physical health inequities experienced by people with a mental health condition worldwide, the need to consider and optimise sleep has been highlighted as a means of improving both physical and mental health status. Sleep recommendations recently developed by the United States' National Sleep Foundation incorporate a range of sleep parameters and enable the identification of 'suboptimal' sleep. Among community-dwelling persons with and without a 12-month mental health condition in Australia, this study reports: [1] the prevalence of 'suboptimal' sleep and [2] rates of sleep assessment by a health care clinician/service and receipt of and desire for sleep treatment.

METHODS

A descriptive study (N = 1265) was undertaken using self-report data derived from a cross-sectional telephone survey of Australian adults, undertaken in 2017.

RESULTS

Fifteen per cent (n = 184) of participants identified as having a mental health condition in the past 12 months. Across most (7 of 8) sleep parameters, the prevalence of suboptimal sleep was higher among people with a mental health condition, compared to those without (all p < 0.05). The highest prevalence of suboptimal sleep for both groups was seen on measures of sleep duration (36-39% and 17-20% for people with and without a mental health condition, respectively). In terms of sleep assessment and treatment, people with a mental health condition were significantly more likely to: desire treatment (37% versus 16%), have been assessed (38% versus 12%) and have received treatment (30% versus 7%).

CONCLUSIONS

The prevalence of suboptimal sleep among persons with a mental health condition in Australia is significantly higher than those without such a condition, and rates of assessment and treatment are low for both groups, but higher for people with a mental health condition. Population health interventions, including those delivered as part of routine health care, addressing suboptimal sleep are needed.

Obstructive sleep apnea and schizophrenia: A systematic review to inform clinical practice

BACKGROUND

Risk factors for obstructive sleep apnea (OSA) are common in people with schizophrenia. Identification and treatment of OSA may improve physical health in this population; however there are no guidelines to inform screening and management.

OBJECTIVES

Systematic review to determine, in people with schizophrenia and related disorders: the prevalence of OSA; the prevalence of OSA compared to general population controls; the physical and psychiatric correlates of OSA, associations between antipsychotic medications and OSA; the impact of treatment of OSA on psychiatric and physical health; and the diagnostic validity of OSA screening tools.

DATA SOURCES

Medline, EMBASE, ISI Web of Science and PsycINFO electronic databases. Cohort, case-control and cross-sectional studies and RCTs reporting on prevalence of OSA in subjects with schizophrenia and related disorders were reviewed.

RESULTS

The prevalence of OSA varied between 1.6% and 52%. The prevalence of OSA was similar between people with schizophrenia and population controls in two studies. Diagnosis of OSA was associated with larger neck circumference, BMI>25, male sex and age>50years. There were no data on physical or psychiatric outcomes following treatment of OSA. The diagnostic utility of OSA screening tools had not been investigated.

CONCLUSION

OSA may be prevalent and potentially under-recognized in people with schizophrenia. Further research is required to determine utility of OSA screening tools, the relationships between antipsychotic medications and OSA and any benefits of treating OSA. We propose a strategy for the identification of OSA in people with schizophrenia and related disorders.

Screening for obstructive sleep apnea among individuals with severe mental illness at a primary care clinic

OBJECTIVE

Obstructive sleep apnea (OSA) is linked to significant morbidity and mortality. OSA has received more attention recently, but the literature on OSA is scant in patients with severe mental illness (SMI). This project was undertaken to improve clinician knowledge and screening of OSA in persons with SMI.

METHOD

One hundred SMI patients attending a primary care clinic were screened for symptoms and risk factors associated with OSA. The Epworth Sleepiness Scale was used to assess daytime sleepiness, and the STOP-Bang score was used to classify those at high risk for OSA.

RESULTS

Sixty-nine percent of patients were found to be at high risk for OSA. Sixteen percent had a previously confirmed diagnosis of OSA. Most patients reported that OSA was never discussed with them, and 71% of those at high risk were willing to be referred for a sleep evaluation.

CONCLUSIONS

Patients with SMI are at high risk for OSA, and screening for OSA appears to be inadequate. This screening can be done easily, seems acceptable to patients and may prove very beneficial as OSA diagnosis and treatment can improve mental and physical health outcomes in SMI patients.