Causes

Many causes for insomnia exist. Sometimes the cause is obvious. Acute, or short-term insomnia, lasts up to a month. Chronic insomnia usually has more complex causes. It can be "secondary," meaning other factors are causing it. Or chronic insomnia can be primary, meaning the insomnia exists by itself and is not caused by psychiatric or chronic conditions or by medications.

Chemical imbalances in the brain could be a factor. Insomnia can be a risk factor for depression. Researchers have found genetic links to chronic insomnia.

Acute insomnia can be brought on by:

• A stressful event.
• Environmental disturbances such as noise or heat or cold.
• Disruption of the sleep/wake cycle, from jet lag or caring for a newborn.
• Side effects of certain medications such as some cough and cold remedies.

Chronic insomnia can be caused by:

• Asthma, rheumatoid arthritis or other chronic pain conditions, and congestive heart failure.
• Mental health disorders such as depression, anxiety or chronic stress.
• Some medications for high blood pressure, decongestants and antidepressants.
• Caffeine, nicotine, alcohol and "recreational" drugs.
• A sleep disorder such as sleep apnea or restless leg syndrome.
• Excessive worrying.
• Disruption of sleep/wake cycle from shift work.
• Poor sleep habits.
• Perimenopause or menopause.
• Incontinence, which may require more trips to the bathroom during the night.

Insomnia is common among pregnant women. This may be because of changes with your hormones, the increased need to urinate, movement of the fetus and the shape of your body, which may alter your sleeping position. Heartburn, leg cramps and sinus congestion are common reasons. This problem may go away after pregnancy.

Medications that may cause insomnia

• Decongestants (cold and allergy medications).
• Antihypertensive (high blood pressure medications).
• Beta-blockers (heart medication).
• Hormones (thyroid medications and birth control pills).
• Asthma medications (inhalers and theophylline).

More on Insomnia

In the Encyclopedia:

This article was reviewed and updated June 2007.