Common Sleep Disorders

Insomnia, sleep apnea, restless legs syndrome, narcolepsy — symptoms, causes, and treatments

What Are Sleep Disorders?

Sleep disorders are conditions that affect the quality, timing, and amount of sleep, leading to daytime distress and impaired functioning. They affect an estimated 50-70 million adults and can significantly impact health, safety, and quality of life.

Many sleep disorders go undiagnosed for years. If you consistently wake feeling unrefreshed or struggle with daytime sleepiness, a sleep disorder may be the cause — not just poor sleep habits.

Common Types of Sleep Disorders

Insomnia

Insomnia is the most common sleep disorder, affecting roughly 1 in 3 adults at some point. It is characterised by difficulty falling asleep, staying asleep, or waking too early — despite adequate opportunity for sleep.

Types: Acute insomnia lasts days to weeks and is usually triggered by stress or a life event. Chronic insomnia lasts 3 or more months and occurs at least 3 nights per week.

Common causes:

• Stress, anxiety, or depression
• Irregular sleep schedule or shift work
• Excessive caffeine or alcohol
• Certain medications (steroids, antidepressants, stimulants)
• Chronic pain or medical conditions

Symptoms:

• Difficulty falling asleep despite being tired
• Waking frequently during the night
• Waking too early and being unable to return to sleep
• Daytime fatigue, irritability, and difficulty concentrating

Treatment: Cognitive Behavioural Therapy for Insomnia (CBT-I) is the most effective long-term treatment — more effective than sleep medication and without side effects. It addresses the thoughts and behaviours that perpetuate insomnia. Improving sleep hygiene is an important first step.

Sleep Apnea

Sleep apnea is a serious disorder where breathing repeatedly stops and starts during sleep. Each pause can last 10-30 seconds and may occur hundreds of times per night, severely fragmenting sleep and reducing oxygen levels.

Types:

• Obstructive Sleep Apnea (OSA) — most common; throat muscles relax and block the airway
• Central Sleep Apnea — brain fails to send correct signals to breathing muscles
• Complex Sleep Apnea Syndrome — combination of both types

Common symptoms:

• Loud snoring (especially with gasping or choking sounds)
• Waking with a dry mouth or headache
• Excessive daytime sleepiness despite a full night of sleep
• Difficulty concentrating or mood changes

Treatment: CPAP (Continuous Positive Airway Pressure) therapy is the gold-standard treatment for OSA — a mask worn during sleep delivers constant air pressure to keep the airway open. Weight loss, positional therapy, and oral appliances are also effective in milder cases. Sleep apnea should always be evaluated by a doctor as it significantly increases the risk of heart disease and stroke.

Restless Legs Syndrome (RLS)

Restless Legs Syndrome causes an irresistible urge to move the legs, typically accompanied by uncomfortable sensations described as crawling, tingling, or aching. Symptoms are worst in the evening and at night when lying down, making it difficult to fall or stay asleep.

Common causes and risk factors:

• Iron deficiency (even without anaemia)
• Pregnancy (affects up to 20% of pregnant women)
• Kidney failure or peripheral neuropathy
• Certain medications (antihistamines, antidepressants, antipsychotics)
• Family history — RLS has a strong genetic component

Treatment: Iron supplementation (if levels are low), regular moderate exercise, reducing caffeine and alcohol, and warm baths before bed. Medication (dopamine agonists) is prescribed for severe cases.

Narcolepsy

Narcolepsy is a chronic neurological disorder that causes the brain to lose control of sleep-wake cycles. People with narcolepsy experience overwhelming daytime sleepiness and may fall asleep suddenly and uncontrollably during normal activities.

Key symptoms:

• Excessive daytime sleepiness (EDS) — the hallmark symptom, present in all cases
• Cataplexy — sudden temporary muscle weakness triggered by strong emotions (laughter, surprise, anger)
• Sleep paralysis — temporary inability to move when falling asleep or waking up
• Hypnagogic hallucinations — vivid, often frightening hallucinations when falling asleep

Treatment: Narcolepsy has no cure but is managed with stimulant medications (modafinil, armodafinil), scheduled naps, and sodium oxybate for cataplexy. Early diagnosis is important as narcolepsy significantly impacts safety — especially driving.

Other Sleep Disorders Worth Knowing

• Circadian rhythm disorders — misalignment between your internal clock and your environment, common in shift workers and frequent travellers
• Parasomnias — disruptive behaviours during sleep including sleepwalking, night terrors, and sleep eating
• Hypersomnia — excessive sleep duration or sleepiness despite adequate night-time sleep
• Periodic Limb Movement Disorder (PLMD) — repetitive limb movements during sleep that disrupt sleep quality, often occurring alongside RLS

Impact on Health

Untreated sleep disorders carry serious long-term health consequences:

• Increased risk of heart disease, stroke, and hypertension
• Higher likelihood of developing type 2 diabetes
• Weakened immune system and slower recovery from illness
• Mental health conditions including depression and anxiety
• Impaired cognitive function, memory, and reaction time
• Increased risk of accidents — drowsy driving causes thousands of road deaths annually

Treatment Options

Treatment depends on the specific disorder but generally includes one or more of:

• Lifestyle changes — consistent sleep schedule, exercise, limiting caffeine and alcohol
• Sleep hygiene improvements — see our full sleep hygiene guide
• CBT-I — first-line treatment for chronic insomnia, highly effective
• CPAP therapy — gold-standard for obstructive sleep apnea
• Medications — used when appropriate and under medical supervision
• Scheduled strategic napping — especially helpful for narcolepsy management

When to See a Doctor

If your main challenge is difficulty falling asleep — and you haven't yet been diagnosed with a disorder — start with these 15 practical tips to fall asleep fast and improve your sleep hygiene before considering further intervention.

Frequently Asked Questions