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[L. insomnia, sleeplessness]

1. A disruption in the amount and quality of sleep that impairs functioning.
2. The subjective experience of insufficient sleep or of sleep that is not refreshing.
SYN: SEE: difficulty initiating and maintaining sleepSEE: sleep disorder; SEE TABLE: Natural and Artificial Stimulants That May Contribute to Insomnia

Roughly half of all people experience some measure of insomnia, however briefly, each year. Ten to 20% of the population experience chronic insomnia.

Insomnia is primary when it occurs in the absence of underlying diseases or conditions. Insomnia more often occurs secondary to a problem, e.g., alcohol or drug dependence, mood disorders, restless legs syndrome, sleep apnea, or travel across time zones.

Some people have trouble falling asleep even when given adequate time and a comfortable place to do so. Others awaken in the middle of the night or early in the morning and have difficulty returning to sleep after waking up. Insomnia is characterized more by the subjective sense that sleep is impaired rather than by objectively measured short sleep duration. Insomniacs also experience alterations in their daytime attention or focus, in their moods, e.g., reporting increased irritability, or their decreased ability to carry out normal daytime functions effectively.

The patient's history, including a carefully documented diary that details sleep behaviors (and their daytime consequences) can help both to diagnose insomnia and to guide therapeutic approaches. Important elements in a sleep diary include factors that interfere with sleep onset or sleep maintenance: how long it takes to fall asleep; the number of nighttime arousals (and the reason for the arousal (such as for nursing mothers, the care they provide for their newborns; or for mature men, the number of times they awaken to urinate). The regularity or irregularity of sleep habits; the patient's comorbid illnesses (esp. sleep apnea) and their treatments; and the consumption of stimulants, alcohol, or other drugs are additional important elements that should be included in a sleep diary by the patient.

Technologies that are occasionally used to aid the diagnosis include wrist actigraphy, in which a monitor is worn by the patient and used to track motor activity during sleep; and polysomnography (PSG). PSG is usually employed only in those patients in whom sleep apnea is suspected.

Many patients with sleep disturbances experience troublesome or intrusive thoughts at night that keep them from resting at night (“My mind is racing.”). Cognitive behavioral therapies (CBTs) may help them to set these thoughts aside until daytime. Other patients sleep poorly because they do not have an established sleep routine. For these patients, sleep hygiene is an effective intervention.

Proven treatments for insomnia include CBTs and hypnotic drugs: both are effective and acceptable to patients. Drug therapies include the use of sedative and hypnotic drugs (including antihistamines such as diphenhydramine; benzodiazepines such as temazepam; benzodiazepine receptor antagonists; antidepressants such as doxepin; melatonin or melatonin receptor agonists such as ramelteon). Daytime drowsiness (drug hangover), alterations in memory, an increased risk of accidents, dry mouth, blurred vision, or constipation are potential side effects of some of these medications. Side effect profiles of the drugs, their potential interactions with alcohol, and the patient's specific responses to drug therapy should be carefully discussed and monitored to achieve the best balance of risk and benefit with each agent.

Several herbal agents have been promoted for their effect on sleep, but there are only limited studies to date to support or recommend rejecting their use.

The prognosis for a restful night's sleep is good for the vast majority of patients who are given appropriate care.

When poor-quality sleep affects daytime functioning, increasing exercise during the day and following sleep hygiene recommendations often improve the quality and duration of sleep. CBT includes educating the patient in sleep hygiene; using relaxation techniques (such as listening to soothing music or closing the eyes and breathing deeply and quietly before bedtime); avoiding activities that the patient identifies as interfering with sleep; restricting sleep time; and keeping of journals to control intrusive or repetitive thoughts. CBT has been shown to be effective within a few weeks of use; its effectiveness is durable, and it also significantly improves sleep.

Natural and Artificial Stimulants That May Contribute to Insomnia
Bright light; sunlight
Coffee, tea, and other caffeinated drinks (like carbonated cola beverages, guarana, and yerba maté, below)
Corticosteroids, such as prednisone
Ephedra sinica—an herbal stimulant
Ephedrine; pseudoephedrine
Ma huang—Chinese name for ephedra
Methamphetamines, including methylphenidate
Modafinil—a drug used to treat narcolepsy
Nicotine, a psychoactive chemical found in tobacco smoke
Selective serotonin reuptake inhibitors (SSRIs), including fluoxetine, paroxetine, sertraline
Theophylline, a medication used to treat asthma
Venlafaxine, an antidepressant
Yerba maté
Yohimbine, an aphrodisiac and body-building drug

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