Common Sleep Disorders

Sleep disorders are medical conditions that consistently disrupt the quantity or quality of sleep. They affect an estimated 50–70 million Americans and significantly increase the risk of hypertension, diabetes, obesity, depression, and accidents.

Disorder	Estimated Prevalence	Commonly Underdiagnosed?
Chronic insomnia	10–15% of adults	Moderate
Obstructive sleep apnea	~26% of adults (30–70 yrs)	Yes — 80%+ undiagnosed
Restless legs syndrome	5–10% of adults	Yes
Narcolepsy	~0.05% of population	Yes — avg 10 yr delay to diagnosis
Circadian rhythm disorders	~3% of adults	Moderate

The biggest barrier to treatment is recognition. Many people assume poor sleep is normal. If sleep problems persist beyond three weeks and affect daytime functioning, evaluation by a physician or sleep specialist is warranted.

Insomnia is defined as difficulty falling asleep, staying asleep, or waking too early, occurring at least three nights per week for at least three months, despite adequate opportunity for sleep.

• Sleep-onset insomnia: Cannot fall asleep within 20–30 minutes of going to bed.
• Sleep-maintenance insomnia: Wakes frequently during the night and struggles to return to sleep.
• Early-morning awakening: Wakes 2+ hours before the intended time and cannot return to sleep.

Common Cause	Category
Anxiety, depression, PTSD	Psychological
Caffeine, alcohol, medications	Substance-related
Pain, acid reflux, nocturia	Medical
Irregular sleep schedule, screen use	Behavioural
Shift work, jet lag	Circadian

The most effective treatment is Cognitive Behavioural Therapy for Insomnia (CBT-I), which outperforms sleep medication for long-term outcomes and is recommended as the first-line treatment by all major sleep guidelines.

Obstructive sleep apnea (OSA) occurs when the throat muscles relax during sleep and partially or fully block the airway. The brain detects the drop in oxygen and briefly wakes the person — sometimes hundreds of times per night — to restore breathing. Most people have no memory of these arousals.

Key symptoms:

• Loud snoring (reported by a bed partner)
• Gasping or choking sounds during sleep
• Unrefreshing sleep despite adequate hours
• Excessive daytime sleepiness
• Morning headaches
• Difficulty concentrating or memory problems

Risk Factor	Notes
Obesity (BMI > 30)	Strongest modifiable risk factor
Male sex	2–3× more common in men
Age > 40	Risk increases progressively
Large neck circumference	>17in men, >15in women
Alcohol use	Relaxes airway muscles further

Diagnosis requires a sleep study (polysomnography) or a home sleep apnea test. First-line treatment is CPAP (Continuous Positive Airway Pressure), which virtually eliminates apnea events when used correctly.

Restless legs syndrome (RLS) is a neurological disorder characterized by an irresistible urge to move the legs, usually accompanied by uncomfortable sensations described as crawling, tingling, burning, or aching. Symptoms are worst in the evening and at night when lying down.

• Diagnosis criteria: Urge to move legs, worsens at rest, relieved by movement, worse in the evening/night.
• Iron deficiency is one of the most common and treatable causes — a ferritin level below 50 ng/mL is often associated with RLS.
• Periodic limb movement disorder (PLMD) often accompanies RLS — involuntary leg movements during sleep that disrupt sleep architecture.

Approach	Notes
Iron supplementation	If ferritin < 50 ng/mL; oral or IV iron
Avoid caffeine and alcohol	Known to worsen symptoms
Dopaminergic medications	First-line Rx for moderate-severe RLS
Gabapentin / pregabalin	Alternative Rx, especially with pain

Tip: Before seeking medication, get your ferritin level tested. A significant proportion of RLS cases improve substantially with iron treatment alone.

Narcolepsy is a chronic neurological disorder causing excessive daytime sleepiness and sudden muscle weakness (cataplexy) triggered by strong emotions. It results from the loss of hypocretin-producing neurons. Average time to diagnosis is over 10 years.

Circadian rhythm sleep-wake disorders include:

• Delayed Sleep Phase Disorder: Cannot fall asleep until 2–6 AM and cannot wake at a conventional time. Common in teenagers and young adults.
• Advanced Sleep Phase Disorder: Falls asleep early (6–8 PM) and wakes very early (2–5 AM). More common in older adults.
• Shift Work Disorder: Misalignment between work schedule and circadian clock.

When to See a Doctor	Possible Condition
Loud snoring + daytime sleepiness	Sleep apnea
Leg discomfort at night relieved by movement	Restless legs syndrome
Sudden muscle weakness with emotion	Narcolepsy
Insomnia > 3 weeks affecting daily life	Chronic insomnia
Acting out dreams physically	REM sleep behaviour disorder

Warning: Never self-diagnose a sleep disorder. Many have overlapping symptoms and require objective testing. A board-certified sleep physician can order a polysomnogram or other studies to provide an accurate diagnosis.