Common Sleep Disorders: A Complete Canadian Guide

12 min read

83 Disorders, Seven Categories

When most people think of sleep disorders, they think of insomnia. Maybe sleep apnoea. But the International Classification of Sleep Disorders (ICSD-3), published by the American Academy of Sleep Medicine and updated in 2023, catalogues 83 distinct sleep disorders across seven major categories.

Those categories are: insomnia disorders, sleep-related breathing disorders, central disorders of hypersomnolence (excessive daytime sleepiness), circadian rhythm sleep-wake disorders, parasomnias (abnormal behaviours during sleep), sleep-related movement disorders, and a catch-all "other" category.

We are not going to cover all 83. What we will do is walk through the ones that affect the most Canadians, the ones that get missed most often, and the ones where your sleep environment (including your mattress) can genuinely make a difference.

The One That Affects 1 in 6 Canadians

A 2024 Canadian population study found that 16.3% of Canadian adults meet the diagnostic criteria for insomnia disorder. That is roughly one in six people. And the trend is heading the wrong direction: Statistics Canada data shows that nighttime insomnia symptoms increased 42% in just eight years, from 16.8% in 2007-2009 to 23.8% in 2014-2015.

Insomnia is not just "having trouble sleeping sometimes." The DSM-5 defines insomnia disorder as difficulty falling asleep, staying asleep, or returning to sleep that occurs at least three nights per week for at least three months and causes clinically significant distress or impairment. The DSM-5 eliminated the old distinction between "primary" and "secondary" insomnia, recognising that insomnia alongside another condition (like anxiety or chronic pain) still needs its own treatment.

What Canadians are using to cope: The same 2024 study found that among Canadian adults, 14.7% had used prescribed sleep medications in the past year, 28.7% had tried natural or over-the-counter sleep aids, 15.6% had used cannabis products for sleep, and 9.7% had used alcohol. That last number is concerning, because alcohol fragments sleep architecture and worsens most sleep disorders.

The Disorder 80% of People Don't Know They Have

Obstructive sleep apnoea (OSA) might be the most underdiagnosed condition in Canadian healthcare. Research estimates that 80% of adults with OSA remain undiagnosed. A study using the Canadian Longitudinal Study on Aging found that among adults aged 45 to 85, 28.1% had combined moderate to severe OSA. Yet only 6.4% of Canadians reported being diagnosed with sleep apnoea by a healthcare professional in 2016-2017, according to Statistics Canada.

That gap between actual prevalence and diagnosis rates means hundreds of thousands of Canadians are walking around with an untreated condition that increases their risk of hypertension, cardiovascular disease, stroke, and type 2 diabetes.

How it works: During sleep, the muscles in your upper airway relax. In people with OSA, this relaxation causes partial or complete airway obstruction, reducing or stopping airflow. The brain detects the drop in oxygen and briefly wakes you (often without you realising it) to reopen the airway. This cycle can repeat dozens or even hundreds of times per night, fragmenting your sleep and stressing your cardiovascular system.

The signs people miss: Loud snoring is the classic signal, but many people dismiss it. Other signs include gasping or choking during sleep (often noticed by a partner), morning headaches, excessive daytime sleepiness despite "enough" time in bed, and difficulty concentrating. Not everyone who snores has sleep apnoea, but everyone with sleep apnoea should be evaluated.

CPAP reality check: Continuous positive airway pressure (CPAP) is the gold standard treatment, but adherence is a problem. Studies show that 46 to 83% of patients are nonadherent when adherence is defined as using the device more than four hours per night. Long-term use rates drop as low as 30%. This is not because CPAP does not work. It works extremely well. The challenge is comfort and tolerance. If you have been prescribed CPAP and are struggling, talk to your sleep clinic about mask options, pressure adjustments, or alternatives like oral appliances.

When Your Legs Won't Let You Rest

Restless legs syndrome (RLS), also known as Willis-Ekbom disease, affects an estimated 5.1% of Canadian adults. Globally, modelling suggests a prevalence of 7.12% among adults aged 20 to 79, roughly 356 million people worldwide. It is twice as common in women as in men.

RLS produces an uncomfortable urge to move the legs, typically worse in the evening and at rest, that is temporarily relieved by movement. For people with moderate to severe RLS, the evening and bedtime hours become the worst part of the day. Trying to sit still and watch television or lie in bed and fall asleep becomes genuinely difficult.

The iron connection: Brain iron deficiency and altered dopamine function are the two accepted pathological elements of RLS. Iron is a critical cofactor in dopamine synthesis, which is why checking ferritin levels is now a standard first step. The RLS Foundation Medical Advisory Board recommends iron therapy when ferritin is below 20 micrograms per litre and suggests considering it when levels are below 75.

The Rarest and Most Misunderstood

Narcolepsy affects roughly 14 per 100,000 people for Type 1 and 65.4 per 100,000 for Type 2, making it uncommon but not as rare as most people assume. Type 1 narcolepsy is caused by the loss of neurons that produce orexin (also called hypocretin), a brain chemical that regulates wakefulness. Over 90% of Type 1 patients have cerebrospinal fluid orexin levels below 110 picograms per millilitre. Type 2 narcolepsy shares the excessive daytime sleepiness but without cataplexy (sudden muscle weakness triggered by emotions) and with less clear mechanisms.

Narcolepsy is not about being tired. People with narcolepsy experience irresistible "sleep attacks," sometimes with vivid hallucinations at sleep onset (hypnagogic hallucinations), sleep paralysis, and (in Type 1) cataplexy. The average time from symptom onset to diagnosis is still measured in years, not months, because the condition is poorly understood by both the public and many general practitioners.

If you find yourself unable to stay awake during the day despite adequate nighttime sleep, falling asleep in unusual situations (mid-conversation, while eating), or experiencing sudden weakness in your muscles during emotional moments, bring these symptoms to your doctor specifically. Do not let them be brushed off as "just being tired."

Things That Go Bump in the Night

Parasomnias are abnormal behaviours that occur during sleep or the transition between sleep and wakefulness. They range from common and mostly harmless to rare and medically significant.

Sleepwalking: Affects 2 to 3% of adults and up to 17% of children under 12. Most childhood sleepwalking resolves on its own. In adults, it can indicate stress, sleep deprivation, or medication side effects. The main risk is injury, and the main intervention is making the sleep environment safe (removing obstacles, securing windows, potentially using door alarms).

Sleep terrors: Roughly 1 in 10 adults experience these at some point. They differ from nightmares in that the person typically does not remember the episode and may sit up screaming or thrashing while still asleep. Like sleepwalking, sleep terrors usually occur during deep non-REM sleep.

REM sleep behaviour disorder (RBD): This is the one that sleep specialists pay the most attention to. RBD involves acting out dreams during REM sleep, when the body should normally be paralysed (a state called atonia). People with RBD may punch, kick, yell, or leap out of bed while dreaming, often injuring themselves or their bed partner.

How Sleep Changes as You Age

Between 43 and 50% of older adults report difficulty falling or staying asleep. But here is an important distinction: poor sleep is common in older adults, but it is not an inevitable consequence of aging. The change is in vulnerability, not destiny.

As you age, several things shift. Your suprachiasmatic nucleus (the brain's master clock) becomes less sensitive to light cues. Melatonin production decreases. Sleep architecture changes: you spend more time in lighter sleep stages and less in deep restorative sleep. You tend to fall asleep earlier and wake earlier. These shifts are normal, but they create more opportunities for sleep to be disrupted by medical conditions, medications, pain, and primary sleep disorders.

The prevalence numbers tell the story. Among older adults, OSA affects up to 70% of men and 56% of women (compared to roughly 15% and 5% in the general adult population). RLS affects 9 to 20%. And REM sleep behaviour disorder, a parasomnia rare in younger adults, becomes the most common parasomnia in the elderly.

If you are over 60 and sleeping poorly, do not accept "that is just getting older" as an answer. Sleep disorders in older adults are treatable, and untreated sleep problems accelerate cognitive decline, increase fall risk, and worsen chronic disease outcomes. Our sleep deprivation guide covers the health consequences of chronic poor sleep.

Getting Help in Canada

Canada has excellent sleep medicine specialists, but access remains a challenge. The country has approximately 2 sleep laboratory beds per 100,000 people nationally, with Ontario having the highest density at 4.1 beds per 100,000 and some territories having none.

The referral process: In most provinces, you need a referral from a physician or nurse practitioner to see a sleep specialist or have a sleep study. Your family doctor is the starting point. Be specific about your symptoms: how long the problem has lasted, what you have already tried, and whether anyone has observed you snoring, gasping, or moving unusually in your sleep.

What to expect: If a polysomnography (in-lab sleep study) is ordered, you will spend a night at a sleep clinic with electrodes monitoring your brain waves, eye movements, muscle activity, heart rate, breathing, and oxygen levels. Home sleep apnoea tests are also available for suspected OSA and are increasingly used to reduce wait times. In Ontario, one sleep study is covered under OHIP every two years.

Wait times: Depending on your region, expect weeks to months for a specialist appointment and potentially 6 to 12 months for an in-lab study. This is frustrating but worth pursuing. In the meantime, improving your sleep environment and habits can help.

While you wait for an assessment, your sleep environment is something you can control right now. A supportive mattress, a dark and cool bedroom, and consistent sleep and wake times are not substitutes for medical treatment, but they create the foundation that treatment builds on. We have been helping Brantford families find the right mattress since 1997, and we are happy to talk through what might work for your situation.