The financial and nonfinancial costs associated with inadequate sleep are substantial. The estimated total financial cost of $17.88 billion represents 1.55 per cent of Australian gross domestic product. The estimated nonfinancial cost of $27.33 billion represents 4.6 per cent of the total Australian burden of disease for the year. These costs warrant substantial investment in preventive health measures to address the issue through education and regulation.

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SUMMARY Sleep inertia, the performance impairment that occurs immediately after awakening, has not been studied previously in relation to decision-making performance. Twelve subjects were monitored in the sleep laboratory for one night and twice awoken by a fire alarm (slow wave sleep, SWS and REM sleep). Decision making was measured over 10 3-min trials using the 'Fire Chief' computer task under conditions of baseline, SWS and REM arousal. The most important finding was that sleep inertia reduces decision-making performance for at least 30 min with the greatest impairments (in terms of both performance and subjective ratings) being found within 3 min after abrupt nocturnal awakening. Decision-making performance was as little as 51% of optimum (i.e. baseline) during these first few minutes. However, after 30 min, performance may still be as much as 20% below optimum. The initial effects of sleep inertia during the first 9 min are significantly greater after SWS arousal than after REM arousal, but this difference is not sustained. Decision-making performance after REM arousal showed more variability than after SWS arousal. Subjects reported being significantly sleepier and less clear-headed following both SWS and REM awakenings compared with baseline and this was sustained across the full 30 min. In order to generalize this finding to real-life situations, further research is required on the effects of continuous noise, emotional arousal and physical activity on the severity and duration of sleep inertia. sleep inertia, decision making, sleepiness, performance.

Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ ME) is a chronic, disabling illness that affects approximately 0.2% of the population. Non-restorative sleep despite sufficient or extended total sleep time is one of the major clinical diagnostic criteria; however, the underlying cause of this symptom is unknown. This review aims to provide a comprehensive overview of the literature examining sleep in CFS/ ME and the issues surrounding the current research fi ndings. Polysomnographic and other objective measures of sleep have observed few differences in sleep parameters between CFS/ME patients and healthy controls, although some discrepancies do exist. This lack of signifi cant objective differences contrasts with the common subjective complaints of disturbed and unrefreshed sleep by CFS/ME patients. The emergence of new, more sensitive techniques that examine the microstructure of sleep are showing promise for detecting differences in sleep between patients and healthy individuals. There is preliminary evidence that alterations in sleep stage transitions and sleep instability, and other physiological mechanisms, such as heart rate variability and altered cortisol profi les, may be evident. Future research investigating the etiology of non-restorative sleep in CFS/ME may also help us to undercover the causes of non-restorative sleep and fatigue in other medical conditions. keywords: Chronic fatigue syndrome, myalgic encephalomyelitis, sleep, non-restorative sleep, sleep disorders, fatigue, sleepiness Citation: Jackson ML; Bruck D. Sleep abnormalities in chronic fatigue syndrome/myalgic encephalomyelitis: a review.

Previous longitudinal studies have demonstrated that poor sleep may precede depression and anxiety. The current study examined the association between self-reported sleeping difficulties and new onset depression and anxiety in young women. A nationally representative sample of 9,683 young women from the Australian Longitudinal Study of Women's Health was analyzed. Women were surveyed in 2000 (aged 22 to 25 years), 2003, 2006, and 2009. Generalized estimating equations were used to examine the association between sleeping difficulties in 2000 and new-onset depression (excluding postnatal depression) and anxiety at each subsequent survey. Significant increased risk of new onset depression (odds ratio (OR)=2.6 in 2003; OR=4.4 in 2006; OR=4.4 in 2009) and anxiety (OR=2.4 in 2006; OR=2.9 in 2009) was found at each follow-up survey in women who reported sleeping difficulties "often" in 2000. Further research is needed to uncover the mechanisms underlying the link between sleep problems and mental health.