According to the Centers for Disease Control, more than 50 million Americans suffer from different sleep disorders, and another 20 to 30 million suffer from intermittent sleep problems. 11% don't feel well-rested every night, and 70% of adults report poor sleep at least one night per month.
The most common are insomnia, restless legs syndrome (RLS), sleep apnea, and narcolepsy. There are over 80 different sleep disorders, and the American Academy of Sleep Medicine classifies sleep disorders into the following categories:
- Insomnias: difficulty falling asleep and staying asleep
- Hypersomnias: causing a person to be extremely sleepy or falling asleep during the day
- Sleep-related breathing disorders: abnormal breathing that affects the quality of sleep
- Circadian rhythm disorders: sufferers don't fall asleep and wake up at normal times
- Parasomnias: events and experiences that occur while falling asleep, sleeping, or waking up
- Sleep movement disorders: movement before or during sleep that prevents restful sleep
Insomnia is defined as having trouble falling asleep or staying asleep. Insomniacs report some or all of the following:
- take a long time to fall asleep
- waking up during the night and not able to fall back asleep
- waking up earlier than desired
- feeling tired throughout the day
The most common form of insomnia is when it's due to another medical condition, which is referred to secondary insomnia. Primary insomnia isn't due to any medical, psychiatric, or environmental cause.
For more information on insomnia, check out our guide to insomnia.
Obstructive sleep apnea is another common sleep disorder where the upper airways become blocked, resulting in the sleeper not breathing for periods of time, which are called apneas.
Some of the common symptoms of sleep apnea are:
- Excessive daytime sleepiness (hypersomnia)
- Loud snoring
- Waking up during the night or in the morning with a dry mouth (a sign of excessive snoring)
- Stop breathing during the night
- A headache in the morning
If you'd like to learn more, check out our guide to sleep apnea.
Restless Legs Syndrome (RLS)
Restless legs syndrome (RLS) is an uncomfortable condition that causes people to move their legs to get rid of the sensation. This usually occurs at night, and often while sleeping, which prevents the sufferer to get restful sleep.
There are two main types of RLS, the first of which is primary RLS, which has no known cause. The other is secondary RLS, which is associated with chronic kidney failure, iron deficiency, spinal cord damage, or peripheral neuropathy (damage to the nerves in your hands and feet, often due to diabetes).
For information, check out our guide to RLS.
Narcolepsy is a rare condition that occurs in two different forms: one with cataplexy, and the other without. Cataplexy is a sudden loss of muscle control when the person can fall or slur their words and is often caused by an emotion such as laughter or some kind of excitement. During cataplexy, the person is awake.
Narcolepsy without cataplexy is often less severe than with cataplexy, and it's a sleep disorder that can cause the sudden onset of sleep, sleep paralysis, hallucinations, and excessive sleepiness. It affects around 1 in 2,000 people. People with narcolepsy can be very tired during the day, and have vivid hallucinations and sleep paralysis while falling asleep and waking up. They also have disturbed sleep at night because the brain doesn't go through the normal flow through the different phases of sleep-people with narcolepsy can go directly from waking to REM (rapid eye movement) sleep, bypassing light sleep and deep sleep.
For more information, check out our guide on narcolepsy.