Insomnia (in-SOM-nee-a) is a disorder in which people have trouble sleeping or getting enough rest.

The Necessity of Sleep

Humans, like all other living organisms, have cycles of activity and rest, which perhaps evolved partly as a response to the cycles of night and day. Many of the body's hormones * and processes are related closely to such daily cycles. Sleep provides the opportunity to rest, to restore certain essential neurotransmitters * , and even to avoid certain predators. Sleep, in short, is necessary to health and even to life.

Yet millions of people have insomnia. They may have difficulty falling asleep or staying asleep through the night, or they may wake up too early or sleep so restlessly that the body and mind are not refreshed. Insomnia is not defined by how long it takes to fall asleep or by how many hours a person sleeps, because these characteristics vary greatly from person to person. Babies may sleep 14 to 17 hours per day or more, and school-age children need between 9 and 11 hours every night. From young adulthood onward seven to nine hours are recommended, though some adults feel they function well with just three to four hours. People are diagnosed with insomnia when sleep problems begin to interfere with daily living, when they can no longer function normally during the day because they are tired or cranky, have no energy, and are unable to concentrate.

Everyone has trouble sleeping sometimes. Young people who are excited about a holiday or stressed about an exam might have trouble falling asleep. Adults who are worried about a sick relative or stressed at work might wake up in the middle of the night and not be able to fall back asleep. These are examples of transient (short-term) insomnia, which are sleep problems that last for one night or even for a few weeks and then disappear. In other cases, episodes of short-term insomnia come and go, which is called intermittent insomnia. But half of all people with insomnia have chronic * insomnia, which is a sleep problem that occurs on most nights for a month or longer.

Insomnia affects people of all ages, but it is most common in older people, especially women. When people travel, start a new job, or move to a new home or school, all of which are changes in routine, they can have trouble sleeping. Physical conditions such as pregnancy, arthritis, the need to urinate frequently, and leg cramps also seem to cause sleep problems. But the most common cause of insomnia is psychological * : anger, anxiety, depression * , and stress keep many people from sleeping well.

How Is Insomnia Treated?

Sleep hygiene

Good sleep hygiene refers to habits, routines, rituals, and practices that support relaxation and regular patterns of sleep.

Tips for Getting a Good Night's Sleep

Tips for Getting a Good Night's Sleep
SOURCE: NIH MedlinePlus, Summer 2015 Issue: Vol. 10 No. 2. Produced by the National Institutes of Health, the National Library of Medicine, and the Friends of the National Library of Medicine. Available at (accessed August 20, 2015). Table by Cenveo Publisher Services. © 2016 Cengage Learning®.

Actions during the day and in the hours just prior to bedtime impact how easy it is to fall asleep, stay asleep, and get restful sleep.

Over-the-counter and prescription sleep aids

Many over-thecounter (OTC) drugs are used for insomnia, most of which contain antihistamine, diphenhydramine, or doxylamine. Various problems attend using these drugs on a regular basis: drug tolerance * ; dependency (meaning a person comes to rely habitually on the drug to assure sleeping well); and various side effects, such as drowsiness the next day. These drugs can also cause problems for users who have certain existing conditions, for example, allergies, asthma, emphysema, chronic bronchitis, and glaucoma * . Most of these drugs should not be used during pregnancy. In addition to OTC drugs, certain herbs are believed to assist sleep, such as valerian. While some people may have allergic responses to herbs, other side effects are not associated with them. But even with herbal remedies, use should be as needed rather than habitual.

Prescription sleep medications are highly effective in treating insomnia, but they have disadvantages, chief among which may be physical and psychological dependency. These controlled substances can be abused and if abused can be dangerous and even life threatening. Prescription sleep medications may contain benzodiazepine (Restoril), eszopiclone (Lunesta), or zolpidem (Ambien). The second and third of these have reduced dependency risk.

For both OTC and prescription sleep aids, users should follow directions carefully, use only as needed rather than habitually, avoid alcohol consumption within several hours of taking the sleep aid, and inform any physician caring for the user of the drug's use. Sleep aids can be effective in special situations, such as in travel across time zones and following certain medical procedures. But they must be used with caution and care and only as needed.

Anti-insomnia drugs

Anti-insomnia drugs
Table by PreMediaGlobal. © 2016 Cengage Learning®.

See also Anxiety and Anxiety Disorders: Overview • Depressive Disorders: Overview • Jet Lag • Sleep Disorders: Overview


Books and Articles

Buxton, Orfeu M., et al. “Sleep in the Modern Family: Protective Family Routines for Child and Adolescent Sleep.” Sleep Health 1 (2015): 15–27. (accessed July 20, 2015).

Izadi, Elahe. “How Much Sleep Do You Need? An Expert Panel Releases Its Recommendations.” Washington Post. February 3, 2015. (accessed July 20, 2015).

Lovejoy, Bess. “The Wee Hours: For Centuries, a Night's Sleep Was Interrupted by a Brief Waking Period.” Lapham's Quarterly. December 8, 2014. (accessed July 20, 2015).


National Heart, Lung, and Blood Institute. “How Much Sleep Is Enough?” (accessed July 20, 2015).

Sleep Education. “Insomnia.” American Academy of Sleep Medicine. (accessed July 20, 2015).


American Academy of Sleep Medicine. 2510 N. Frontage Rd., Darien, IL 60561. Telephone: 630-737-9700. Website: (accessed July 20, 2015).

American Insomnia Association. One Westbrook Corporate Center, Suite 920, Westchester, IL 60154. Telephone: 708-492-0930.Website: (accessed July 20, 2015).

American Sleep Association. 1002 Lititz Pike, #229, Lititz, PA 17543. Website: (accessed July 20, 2015).

Office on Women's Health. Department of Health and Human Services, 200 Independence Ave., SW Room 712E, Washington, DC 20201. Telephone: 202-690-7650. Website: (accessed July 20, 2015).

* neurotransmitters (nur-otrans-MIH-terz) are chemical substances that transmit nerve impulses, or messages, throughout the brain and nervous system and are involved in the control of thought, movement, and other body functions.

* hormones are chemical substances that are produced by various glands and sent into the bloodstream carrying messages that have certain effects on other parts of the body.

* chronic (KRAH-nik) means lasting a long time or recurring frequently.

* depression (de-PRESH-un) is a mental state characterized by feelings of sadness, despair, and discouragement.

* psychological (SI-ko-LOJ-i-kal) refers to mental processes, including thoughts, feelings, and emotions.

* glaucoma is a group of disorders that cause pressure to build in the eye, which may result in vision loss.

* tolerance (TALL-uh-runce) is a condition in which a person needs more of a drug to feel the original effects of the drug.

Disclaimer:   This information is not a tool for self-diagnosis or a substitute for professional care.

(MLA 8th Edition)