Obstructive sleep apnoea and schizophrenia--a research agenda

Schizophrenia is associated with significantly increased physical morbidity and mortality particularly secondary to cardiometabolic disorders. In people with schizophrenia, rates of obesity and the metabolic syndrome are high compared to the general population. Whilst the weight gain secondary to antipsychotic medication is largely to blame, other factors include inactivity, poor diet and possibly the illness itself. Obstructive sleep apnoea (OSA) is a common and frequently under-recognized condition which may be associated with disabling symptoms including daytime sleepiness, cognitive impairment, depression, anxiety and long term increases in morbidity and mortality secondary to cardiometabolic disease. As the primary risk factor is obesity, elevated rates of sleep apnoea would therefore seem likely in association with schizophrenia. Thus, OSA might represent a treatable cause of psychiatric and physical co-morbidity in patients with schizophrenia. A review of the literature revealed a paucity of quality research in this area. Available data suggest increased rates of sleep apnoea in schizophrenia and that psychotic symptoms may improve when co-morbid sleep apnoea is treated. Health practitioners may be unaware of the need to screen for sleep apnoea in patients with schizophrenia and the disorder may be significantly under-recognised. Research is required to clarify the epidemiology, consequences and management of sleep apnoea in association with schizophrenia.