Sleep disorders - overview
Insomnia; Narcolepsy; Hypersomnia; Daytime sleepiness; Sleep rhythm; Sleep disruptive behaviors; Jet lag
Sleep disorders are problems with sleeping. These include trouble falling or staying asleep, falling asleep at the wrong times, too much sleep, and abnormal behaviors during sleep.
You tuck yourself under the covers, turn out the light, and look forward to eight hours of blissful slumber. But, after turning for hours you're still exhausted, and no closer to sleep than when you first got into bed. Let's talk toady about sleep disorders. Sleep disorders fall into four basic categories. The scenario I described, in which you toss and turn because you can't fall asleep, is called insomnia. Another type of insomnia is when you wake up in the middle of the night and can't get back to sleep. Sometimes people get insomnia for a night or two because they're stressed out over a big meeting at work, or they're excited about an upcoming trip. Others can't sleep night after night, and that's called chronic insomnia. People with the second category of sleep disorders have a hard time staying awake during the day, even if they slept well the night before. This is called hypersomnia. Sometimes doctors can't find a cause for hypersomnia. But in many cases, a health condition like fibromyalgia, a thyroid problem, a disease like mononucleosis, obesity, or obstructive sleep apnea, can make you sleepy. If you notice a co-worker is nodding off in the middle of meetings, he might have narcolepsy, a sleep disorder that causes people to sleep uncontrollably at inappropriate times during the day. Narcolepsy isn't only embarrassing, it can be dangerous if you nod off behind the wheel of a car. A sleep rhythm problem means that you can't stick to a normal sleep schedule. Maybe you work the night shift at your job, or you're always traveling to different time zones and are constantly battling jet lag. Well, whatever the cause, the lack of a normal sleep pattern is called a sleep rhythm disorder. And finally, there are the types of sleep disorders that wake you up with a jolt in the middle of the night, and, these are called parasomnias, and they can severely interrupt your sleep. You may walk in your sleep, or act out your dreams. Children often have night terrors, in which they wake up from a deep sleep in a terrified state. The good news is that you don't have to live on fewer hours of sleep, because there are decent treatments for sleep disorders. If you're struggling to sleep throughout the night, and dragging through the day as a result, talk to your doctor, who can refer you to a sleep specialist for an evaluation.
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
Hypersomnia is a condition in which people have excessive daytime sleepiness. This means 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. It can also occur 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
- 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
Abnormal behaviors during sleep are called parasomnias. They are fairly common in children and include:
Avidan AY. Sleep and its disorders. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 101.
Sateia MJ, Thorpy MJ. Classification of sleep disorders. In: Kryger M, Roth T, Dement WC, eds. Principles and Practice of Sleep Medicine. 6th ed. Philadelphia, PA: Elsevier; 2017:chap 61.
Last reviewed on: 1/29/2020
Reviewed by: Allen J. Blaivas, DO, Division of Pulmonary, Critical Care, and Sleep Medicine, VA New Jersey Health Care System, Clinical Assistant Professor, Rutgers New Jersey Medical School, East Orange, NJ. Review provided by VeriMed Healthcare Network. Internal review and update on 08/20/2021 by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.