Sleep disorders are problems with sleeping, including trouble falling or staying asleep, falling asleep at the wrong times, too much sleep, or abnormal behaviors during sleep.
Causes, incidence, and risk factors
There are more than 100 different sleeping and waking disorders. They can be grouped into four main categories:
- Problems falling and staying asleep (insomnia)
- Problems staying awake (excessive daytime sleepiness)
- Problems sticking to a regular sleep schedule (sleep rhythm problem)
- Unusual behaviors during sleep (sleep-disruptive behaviors)
PROBLEMS FALLING AND STAYING ASLEEP
Insomnia includes trouble falling asleep or staying asleep. Episodes may come and go, last up to 3 weeks (be short-term), or be long-lasting (chronic).
PROBLEMS STAYING AWAKE
People with excessive daytime sleepiness feel tired during the day. Symptoms that are not caused by a lack of sleep or interrupted sleep are called hypersomnia.
Causes of this problem include:
- Medical conditions such as fibromyalgia and low thyroid function
- Mononucleosis or other viral illnesses
- Narcolepsy and other sleep disorders
When no cause for the sleepiness can be found, it is called idiopathic hypersomnia.
PROBLEMS STICKING TO A REGULAR SLEEP SCHEDULE
Problems may also occur when you do not stick to a regular sleep and wake schedule. This occurs when people travel between time zones and with shift workers who are on changing schedules, especially nighttime workers.
Disorders that involve a disrupted sleep schedule include:
- Irregular sleep-wake syndrome
- Jet lag syndrome
- Paradoxical insomnia (the person sleeps a different amount than they think they do)
- Shift work sleep disorder
Abnormal behaviors during sleep are called parasomnias. They are fairly common in children and include:
- Sleep terrors
- REM sleep-behavior disorder (a person moves during REM sleep and may act out dreams)
Signs and tests