Sleep disorders - overview

Insomnia; Narcolepsy; Hypersomina; Daytime sleepiness; Sleep rhythm; Sleep disruptive behaviors; Jet lag

There are more than 100 different sleeping and waking disorders. They can be grouped into 4 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

Hypersomnia is a condition in which people have excessive daytime sleepiness, meaning that they feel tired during the day. Hypersomnia can also include situations in which a person needs to sleep a lot. This may be due to other medical conditions, but can also be due to a problem in the brain. Causes of this problem include:

• Medical conditions, such as fibromyalgia and low thyroid function
• Mononucleosis or other viral illnesses
• Narcolepsy and other sleep disorders
• Obesity, especially if it causes obstructive sleep apnea

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
• Delayed sleep phase, as in teenagers who go to sleep very late at night and then sleep until noon
• Advanced sleep phase, as in older adults who go to sleep early in the evening and wake up very early

SLEEP-DISRUPTIVE BEHAVIORS

Abnormal behaviors during sleep are called parasomnias. They are fairly common in children and include:

• Sleep terrors
• Sleepwalking
• REM sleep-behavior disorder (a person moves during REM sleep and may act out dreams)