Introduction
3.1
Approximately one in five Australians are estimated to be affected by a major sleep disorder. These include: Obstructive Sleep Apnoea (OSA), insomnia, Restless Legs Syndrome (RLS), circadian rhythm disorders and central disorders of hypersomnolence.
3.2
As well as the immediate effects of sleepiness and fatigue, sleep disorders may also contribute to other health conditions, including: diabetes, obesity, mental health and cardiovascular disease.
Types, Causes and Symptoms of Sleep Disorders
Obstructive Sleep Apnoea
3.3
The sleep disorder, OSA occurs due to obstructions of the upper airway and is ‘characterised by snoring’ and ‘repetitive periods of obstructed breathing during sleep.’ The disorder, OSA was described as a chronic health disorder, with symptoms including: ‘sleep disruption, snoring and daytime sleepiness.’ During sleep, a ‘reduction in oxygen levels,’ brief awakenings, and ‘mechanical stresses on the heart and lungs’ can also occur.
3.4
Depending on the frequency of impaired breathing events that occur during sleep, the severity of OSA can be measured as mild, moderate, or severe. The Canberra Sleep Clinic stated that the severity of OSA symptoms experienced do not necessarily provide an indication of ‘the severity of the apnoea measured by [a] sleep study.’
3.5
Men and women may experience different symptoms of OSA. As a result, Professor Robert Adams, Professor Gary Wittert, and Dr Sarah Appleton (Adams, Wittert, and Appleton) were concerned that ‘current screening tools may miss many with significant OSA, especially women.’
3.6
The sleeping disorder, OSA is caused by physiological and age-related factors, with ‘weight [being] the most profound risk factor.’ Further, the University of Western Australia (UWA) Centre for Sleep Science (CSS) stated that there are a ‘whole cascade of reasons why men are more susceptible’ to OSA than women, elaborating that:
Men carry their fat a bit differently. [Men] tend to carry it up higher, whereas women carry it down lower. It's not good to have it around your neck for sleep apnoea. There are also different kinds of hormonal reasons. Women have hormones which drive breathing and muscles … It does change post menopause; women do start becoming more susceptible.
Insomnia
3.7
Sleep Matters stated that ‘insomnia is not just the occasional night of poor sleep that we all experience but [it] is a chronic condition that doesn't tend to resolve without treatment.’ Insomnia is characterised by ‘chronic difficulties in initiating or maintaining sleep, or frequent early [waking], resulting in impairment of daytime functioning.’
3.8
Insomnia can be experienced as a symptom of another condition, but it may also be diagnosed as a sleep disorder independent of other existing health conditions. The UWA School of Psychological Science (SPS) stated that people may continue to experience insomnia even after co-morbid OSA has been treated.
3.9
Insomnia which persists for less than three months is described as episodic (or acute) and is often associated with events such as ‘occupational stress, personal losses, [or] bereavement.’ Insomnia is considered chronic if symptoms persist beyond three months. Adams, Wittert, and Appleton stated ‘objectively measured short sleep duration has been shown to be a risk factor for developing into the more severe form of chronic insomnia.’
3.10
The UWA-CSS stated that insomnia is caused by a combination of anatomical (for example, the effect of exposure to light on the ‘body clock’) and behavioural factors. In regard to the behavioural elements of insomnia, Neuroscience Research Australia (NeuRA) and Sleep Matters highlighted the ‘vicious cycles’ of thought and anxiety that insomnia patients experience. Ms Rosemary Clancy stated that ‘the focus on quantity [of sleep] just creates performance anxiety around sleep and people then start to become fearful of it.’
Restless Legs Syndrome
3.11
The movement disorder of RLS is ‘characterised by an irresistible urge to move the legs, that is worse at night, particularly when trying to get to sleep.’ Mr Graham Revill noted that it can also affect the arms and the torso, and that ‘the feelings and pain are associated with lying down and trying to relax or sitting for some time.’
3.12
Dr Cunnington and Dr Swieca stated that the ‘symptoms of [RLS] are also variable and unpredictable. This can result in people unexpectedly having a very poor night’s sleep, and having difficulty performing work-related tasks the subsequent day.’ In severe cases, these involuntary and periodic movements can result in a ‘very disabling’ experience for patients.
Circadian Rhythm Sleep Disorders
3.13
The circadian rhythm is also known as the sleep-wake cycle. Austin Health and the Institute for Breathing and Sleep discussed Shift Work Sleep Disorder, which refers to the misalignment of sleep and wake times with the circadian rhythm due to shift work requirements. The symptoms include insomnia and/or excessive sleepiness.
3.14
Another circadian rhythm sleep disorder is ‘Non 24 Hour Sleep Wake Disorder’ (N24), also known as Hypernychthemeral Syndrome, where ‘an individual's biological clock fails to synchronise to a 24-hour day.’ In people who experience N24, sleep times gradually delay each day.
3.15
An inquiry participant outlined their child’s experience of being unable to adjust to the day-night cycle and stated:
… the first symptoms of N24 usually noticed are periodic night-time insomnia and excessive daytime sleepiness. Due to the cyclical nature of the disorder, some affected persons will tend to feel normal for periods of days to weeks when their body’s rhythm is synchronized with the rhythm of society around them. As the individual’s body once again desynchronises … the insomnia and excessive daytime sleepiness will return.
3.16
The sleep disorder of N24 is more common in visually impaired persons where it is due to the lack of light ‘input to the circadian pacemaker.’ In contrast, N24 is rare in sighted persons and there is ‘limited knowledge’ of the cause in these cases.
Central Disorders of Hypersomnolence
3.17
Central disorders of hypersomnolence are neurological disorders and include: narcolepsy type I (generally with cataplexy), narcolepsy type II (without cataplexy), and idiopathic hypersomnia.
3.18
The Sir Charles Gairdner Hospital (SCGH) described narcolepsy ‘as a neurological condition where some of the circuitry within the brain unstably switches between sleep and wakefulness.’
3.19
Narcolepsy type I is thought to be caused by the ‘autoimmune selective destruction of’ the cells that produce hypocretin, a chemical in the brain known for ‘regulating wake and sleep.’ Dr Cunnington and Dr Swieca stated that ‘narcolepsy without cataplexy and idiopathic hypersomnia are less well characterised, with the exact biological mechanisms being unclear.’
3.20
Symptoms of narcolepsy include: excessive daytime sleepiness (often in the form of a ‘sleep attack’, where the sleepiness is sudden and overwhelming), sleep paralysis, hallucinations, and automatic behaviour. In cases of narcolepsy type I, this may also involve cataplexy.
3.21
Professor Grunstein stated that cataplexy involves the sudden loss of muscle tone. The SCGH stated that during cataplexy, the patient’s ‘legs go wobbly and, in extreme cases, they’ll fall to the ground and be awake but unable to move for 30 seconds’ or more. The triggers can vary depending on the person, and can occur ‘particularly after laughter or emotions.’
3.22
Idiopathic hypersomnia is characterised by an ‘excessive sleep need’, often ‘greater than 12 hours a day.’ Sleep Disorders Australia and Hypersomnolence Australia (SDA-HA) stated that ‘idiopathic hypersomnia is a neurological disorder diagnosed by identifying key clinical features’ and excluding other possible conditions.
Prevalence of Sleep Disorders in Australia
3.23
The Royal Australasian College of Physicians (RACP) advised that ‘the two most common sleep disorders are [OSA] and insomnia.’ In 2017, Deloitte Access Economics (Deloitte) estimated the combined prevalence of OSA, RLS and insomnia to be 22.4 per cent of the Australian population.
3.24
There are a number of challenges to accurately estimating the number of Australians who experience a sleep disorder. The Western Australian Pregnancy Cohort Study (Raine Study) stated that ‘a challenge in stating prevalence estimates is what diagnostic cut-off to use to describe presence or absence of disease.’
3.25
In addition, the UWA-SPS explained that because people may have multiple sleep disorders, prevalence rates are ‘often confounded by co-occurrence’ of sleep disorders, which ‘makes the [overall] figures and … estimates quite challenging.’ For example, the Australasian Sleep Association stated that insomnia ‘has a high co‑morbidity (30 to 40 per cent) with other sleep disorders such as [OSA], and [RLS].’
Prevalence of Obstructive Sleep Apnoea
3.26
The 2016 Sleep Health Foundation (SHF) National Survey estimated that 8.3 per cent of the Australian adult population has been diagnosed with OSA. The prevalence of OSA increases with age, with the SHF National Survey highlighting that 5 per cent of 18 to 24 year olds have been diagnosed with OSA compared to 12 per cent of people over 65 years of age. In addition, the SHF National Survey also outlined significant gender based variation in the prevalence of OSA with 12.9 per cent of men and 3.7 per cent of women having been diagnosed with OSA.
3.27
The RACP stated that the SHF National Survey results ‘also noted a large group of participants with likely undiagnosed, symptomatic OSA.’ NeuRA similarly stated that more than 80 per cent of people with OSA remain undiagnosed.
3.28
Further, Adams, Wittert, and Appleton stated a population study had found that over 50 per cent of men aged over 40 years had previously undiagnosed OSA. Despite the apparent prevalence of the condition, ‘only 11 per cent of men aged over 40 years report having been given a diagnosis of OSA.’
3.29
The Adelaide Institute for Sleep Health (AISH) stated that data for OSA in women and sleep disorders in Aboriginal and Torres Strait Islander peoples was lacking:
The negative health burden of OSA in women is under-researched and not well understood as the majority of epidemiological data are dominated by male cohorts. There is [also] a significant gap in research into the health impacts of sleep disorders in Indigenous Australians.
Prevalence of Restless Legs Syndrome
3.30
The SHF National Survey estimated that 17.6 per cent of Australian adults experience RLS. Using a narrower definition of RLS, Deloitte estimated that 2.8 per cent of the Australian population have RLS that is not the symptom of another disorder or condition.
Prevalence of Insomnia
3.31
Deloitte estimated that 11.3 per cent of the Australian population experience insomnia without comorbidities. The SHF National Survey estimated episodic insomnia to be experienced by 20 per cent of Australian adults. Adams, Wittert, and Appleton stated that the prevalence of chronic insomnia in Australia was unknown, but is likely to be at 10 per cent.
Prevalence of Central Disorders of Hypersomnolence
3.32
The SCGH stated that narcolepsy ‘affects one in 2000 people, roughly.’ Dr David Cunnington and Dr John Swieca also indicated that approximately 0.03 to 0.05 per cent of the population are affected by ‘narcolepsy with cataplexy’, however ‘exact prevalence data [is] not clear’ for narcolepsy due to a lack of research.
3.33
The SDA-HA stated that figures relating to narcolepsy rates may be overstated. The SDA-HA stated that general practitioners may be miscoding unexplained cases of excessive daytime sleepiness and ‘genuine cases of idiopathic hypersomnia … as narcolepsy.’ Elaborating further, SDA‑HA stated that this may distort the prevalence of idiopathic hypersomnia and narcolepsy in Pharmaceutical Benefits Scheme (PBS) and Medicare Benefits Schedule (MBS) data:
Australian government authorities (including the Therapeutic Goods Administration) rely on statistics from Australia’s PBS and MBS yet these records do not reflect the true prevalence of idiopathic hypersomnia and narcolepsy. Therefore, one could get a false impression of an epidemic of "narcolepsy" when in fact if you were to isolate the true narcoleptics the number would be quite small.
Intersection with Other Medical Conditions
3.34
The impacts of a sleep disorder are not limited to the immediate consequences of tiredness and fatigue, but may also be linked to longer-term health issues. The RACP stated that ‘a range of sleep disorders (insomnia, [RLS], and [OSA]) can contribute to heart disease, obesity, depression, early onset dementia and other serious health conditions.’
3.35
In addition, the relationship between sleep disorders and other medical conditions may be bidirectional. That is, patients with a sleep disorder may have a higher risk of developing a chronic health condition, and patients with a chronic health condition may have a higher risk of developing a sleep disorder. To illustrate this, the UWA-SPS stated that ‘type II diabetes … is a risk factor for apnoea, and sleep apnoea is a risk factor for type II diabetes.’
3.36
Adams, Wittert and Appleton expanded on the bidirectional relationship between OSA and other chronic health conditions, and stated:
Among men with multiple medical conditions (multimorbidity), such as diabetes or heart disease, undiagnosed OSA was present in 70 per cent. Those with severe OSA were over six times more likely to have three or more other chronic diseases than those men without OSA.
3.37
Obesity is a significant contributor to the development of OSA in the population. Dr Subash Heraganahally stated that obesity has ‘been well recognised as an important pre-requisite risk factor … for the development of [OSA].’ The AISH commented on the impact that weight gain and ageing has on prevalence rates of sleep disorders, stating:
… OSA, insomnia and sleep restriction have increased by 30 to 80 per cent in the last two decades (affecting at least four million Australian adults) because of combined effects of increasing rates of people who are overweight and obese, and our ageing population.
3.38
The RACP considered OSA to be an ‘emerging cardiovascular risk factor.’ The Charles Perkins Centre added that OSA ‘increases the risk that a person will develop high blood pressure, heart disease, stroke, and increases deaths from heart disease.’ Highlighting the current limitations of research into OSA, Associate Professor Darren Mansfield stated that ‘the evidence of benefit for treatment of OSA on cardiovascular health remains unclear.’
3.39
In some cases, while an association between OSA and other chronic health conditions has been found, the details of this relationship are not well understood. For example, the Charles Perkins Centre stated that ‘OSA patients have higher rates of cancer and cancer mortality but it is unclear why.’ In addition, the RACP stated that a lack of clarity in the role of OSA in heart arrhythmia is due to a ‘paucity of data’ that prevents the establishment of ‘whether OSA is a risk factor for atrial fibrillation independent of obesity and other established risk factors.’
3.40
In addition to physical health conditions, sleep disorders have been linked to mental health conditions. Sleep Matters stated that ‘it is quite rare that we would be referred a case of insomnia that isn’t comorbid with other conditions … [such as] depression and/or anxiety.’ Similarly, Adams, Wittert, and Appleton stated that there is an association between depression and OSA:
With regard to sleep apnoea, research in middle-aged and older men has shown the severity of depressive symptoms increases with the severity of sleep apnoea. It has also shown that when insomnia is co-morbid with sleep apnoea the prevalence and severity of depression increases significantly.
Personal Accounts of Living with Sleep Disorders
3.41
The Committee received evidence from individuals that detailed their experiences of living with a sleep disorder. These included patients living with OSA, RLS, idiopathic hypersomnia, narcolepsy and circadian rhythm disorders.
3.42
Those living with a sleep disorder spoke about the stigma and lack of understanding they experienced. An inquiry participant who is experiencing OSA stated that ‘the issue of snoring is often the subject of great frivolity and embarrassment to the sufferer’, and was concerned that others would not consider OSA to be a medical issue.
3.43
As sleep disorders may not be easily diagnosed, the parent of a child experiencing N24 described the difficulty with obtaining support at school, stating that ‘we were judged as bad parents as we did not have any diagnosis to support our claims.’
3.44
The parent also described the impact that caring for a sleep disorder patient can have on family members, stating that they were exhausted and could no longer provide home schooling:
We had to obtain an exemption from education as the exhaustion of her mother meant she could no longer teach her as she was fearful of developing a sleep disorder of her own.
3.45
Mr Graham Revill stated that he felt that obtaining treatment or relief for his RLS would have conflicted with his employment:
… I doubt if my employer would have accepted “lack of sleep” as a reason for sick leave. I would not have been willing to ask my doctor for such a certificate because there was a story going around that if you told your doctor that you were exhausted because of inability to sleep then the doctor would report me and my driver’s licence would be cancelled or suspended. I couldn’t risk losing my job.
3.46
A teacher living with a sleep disorder stated that whilst their employer is ‘wonderfully supportive’ of their part-time arrangements, working at a school meant there was ‘no capacity to make accommodations for my disorder.’ The teacher added that ‘a nap would allow me to clear the fog and be a more productive employee, but I am unable to do so at work.’
3.47
Inquiry participants stated that narcolepsy is not recognised as a disability for the purposes of the Disability Support Pension (DSP) or the National Disability Insurance Scheme. An inquiry participant stated that:
The most suitable payment is [the DSP] which currently does not have the condition, or any other sleep disorder listed as a medical condition to begin with. This means that they have to try to relate their impairments to the current impairment tables, [and] then be assessed under those tables by an assessor who in most cases hasn’t even heard of narcolepsy, never mind have any concept of how debilitating the condition can be.
3.48
The inquiry participant further stated that ‘due to their excessive sleepiness … [narcolepsy patients] are unable to manage the requirements for Newstart eligibility.’
Box 3.1: Living with Narcolepsy
Individuals experiencing narcolepsy described a wide range of impacts. Ms Eliza Wells stated that ‘every aspect of my life has been affected [by narcolepsy]; finances, work, education, social connection, relationships, home, leisure and obviously health.’
For some people with narcolepsy they may experience symptoms of the condition for a long period before they receive a diagnosis of narcolepsy. The delayed diagnosis can occur due to their attribution of their symptoms to other causes, such as ‘work or the busyness of raising a family’ or a lack of awareness of narcolepsy amongst medical professionals. Ms Fiona Mobbs stated that after her diagnosis, her ‘sleep specialist said … why are you not back at work? Why are you still tired?’ In the case of children, Mrs Monica Kurth described her daughter not mentioning symptoms such as feeling ‘floppy’, elaborating that ‘kids … don't know or say this is an unusual thing that's happening to me.’
Difficulty in accessing medical care for narcolepsy, particularly in regional areas, was described in some personal accounts. After being diagnosed in a metropolitan area and moving to a regional town, Ms Wells found that the ‘local GPs … not only have no understanding of narcolepsy, they also appear to have little to no interest in gaining one.’ Mrs Pamela Bird stated that there are ‘very few’ specialists in Hobart, and her family needed to travel to Melbourne for medical care.
Those living with narcolepsy stated they felt a lot of stigma attached to their disorder. The disorder is not immediately obvious, as ‘the condition functions under the aesthetic of normality.’ Mrs Angela Stewart stated ‘there’s a nasty social stigma of being a bludger attached to patients diagnosed with invisible disorders.’ Addressing these sentiments, Ms Mobbs stated that ‘we're not lazy; we're people, who want to do a lot, trapped inside bodies that cannot.’
Some personal accounts also outlined experiences of cataplexy. Mrs Pamela Bird stated that her daughter may have cataplectic episodes ranging from a few times a day, to 30 to 40 times a day. Describing the feeling of embarrassment when having a cataplectic episode in public, Ms Mobbs stated that:
If someone is behind me when I'm having [a cataplectic episode], it would just look like I'm drunk. It's extremely embarrassing. You just want to go somewhere where no-one can see what's happening.
Those experiencing cataplexy stated that they avoided triggers in order to manage their symptoms. Mrs Bird stated that she saw her ‘bright, bubbly child become a hollow shell.’ Ms Laura Thompson stated that she muted her positive emotions in response to her cataplexy:
Unfortunately my cataplexy is associated with positive emotions, mostly laughter, sometimes pride, anticipation or joy. Just imagine holding yourself back from the happiest moments in your life in fear that you will experience this terrifying attack.
Inquiry participants stated they found it difficult to remain in the workforce. Ms Fiona Mobbs stated ‘my workplace was extremely unsupportive. I had to resign from my job last year in May.’ Another inquiry participant further stated that maintaining employment makes maintaining a social and family life difficult:
Over time, it is possible to learn to live with the conditions but maintaining full-time employment comes at the cost of social and family life. It is very hard to achieve a work-life balance when you constantly feel exhausted and you find that sleep is not refreshing.
Some inquiry participants had the opportunity to access Sodium Oxybate (marketed as Xyrem). Mr Aaron Schokman, speaking about the effects of Sodium Oxybate, stated ‘my symptoms … are managed, and I have been able to work full time, socialise and complete my studies.’ Sodium Oxybate remains a restricted and expensive medication in Australia, with one inquiry participant stating that ‘I am still beholden to my mother for intermittent financial assistance. My fulltime wages simply do not cover the costs.’
Ms Noeline Bakels also questioned the lack of PBS subsidy for Sodium Oxybate, asking: ‘why not spend the money on helping them become functioning members of society rather than dependent on the welfare system living barely half a life?’
Concluding Comment
3.49
Estimates suggest that more than one in five Australians live with a sleep disorder, with Obstructive Sleep Apnoea (OSA) and insomnia accounting for the majority of these cases. Despite the prevalence of these conditions, there is limited data available about the occurrence of sleep disorders within specific population groups. In particular, there is a need for further research into the prevalence and experience of sleep disorders among women and Aboriginal and Torres Strait Islander peoples.
3.50
Gaining adequate, quality sleep is a requirement for maintaining long-term good health. It is therefore not surprising that a sleep disorder causing continually disturbed sleep can have serious health implications. The Committee heard that these impacts include an increased risk of conditions such as diabetes, obesity, and cardiovascular disease.
3.51
In particular, OSA appears to be closely connected to obesity. The Committee is concerned that OSA’s relationship with weight gain, as well as ageing, will result in the prevalence of OSA rising alongside increasing rates of obesity and an ageing population in Australia.
3.52
Emerging evidence about the connection between sleep disorders and cardiovascular disease was also raised. The Committee is interested in the relationship between sleep and cardiovascular health as sleep is a risk factor for heart disease that may potentially be treated early. There are still, however, many research questions to be answered, including the impact that managing a sleep disorder can have on the risk of cardiovascular disease.
3.53
The Committee also received information that there is a close relationship between mental health and sleep disorders, for example chronic insomnia may result from conditions such as anxiety and depression. In many cases this relationship may be bidirectional where disturbed sleep exacerbates a mental health condition and this condition also increases the impact of a sleep disorder.
3.54
The Committee was concerned to hear that many people with sleep disorders have experienced stigma as a result of their condition. Assumptions made about a person with a sleep disorder may stem from a lack of understanding in the community about these conditions and how they can be managed.
3.55
The Committee appreciated the individuals who shared their personal experiences of living with a sleep disorder, or caring for a family member or friend with a sleep disorder. Their accounts highlight the debilitating and wide-ranging effects that sleep disorders can have on lifestyle.