Chronic insomnia is often caused by one or more of the following

• Another disease or mood disorder. The most common causes of insomnia are depression and/or anxiety disorders. Neurological disorders such as Alzheimer's or Parkinson's disease can also have insomnia as a symptom. Chronic insomnia can result from arthritis, asthma, or other medical conditions in which symptoms become more troublesome at night, making it difficult to fall asleep or stay asleep.
• Various prescribed and over-the-counter medications that can disrupt sleep, such as decongestants, certain pain relievers, and steroids.
• Sleep-disrupting behavior such as drinking alcohol, exercising shortly before bedtime, ingesting caffeine late in the day, watching TV or reading while in bed, or irregular sleep schedules due to shift work or other causes.
• Another sleep disorder, such as sleep apnea or restless legs syndrome.

Some people, however, have primary chronic insomnia. This condition is linked to a tendency toward being more "revved up" than normal (hyperarousal). These people may have heightened secretion of certain hormones, higher body temperatures, faster heart rates, and a different pattern of brain waves while they sleep.

Doctors diagnose insomnia based mainly on sleep history, often by reviewing a sleep diary. An overnight sleep recording may be required if another sleep disorder is suspected. Doctors also will try to diagnose and treat any other underlying medical or psychological problems as well as identify behaviors that might be causing the insomnia.

Often, people who have insomnia enter into a vicious cycle - because of having trouble sleeping in previous nights, they become anxious at the slightest sign that they may not be falling asleep right away.

That anxiety can make it more difficult for them to fall asleep. The more time they spend in bed not sleeping, and watching the clock, the more their anxiety - and sleeplessness - increases.

To break that cycle of anxiety and negative conditioning, experts recommend going to bed only when you're sleepy. If you can't fall asleep (or fall back to sleep) within 20 minutes, get out of bed and go into another room where you can pursue a relaxing activity until you feel sleepy again. Then return to bed. This reconditioning therapy has been shown to be an effective way to treat insomnia.

Another effective behavioral strategy for some people is relaxation therapy. For example, progressively tense and then relax each of the muscle groups in your body before sleep. Another method is to focus on breathing deeply. Relaxation therapy can provide a needed slowing down period so that you are indeed sleepy when the desired bedtime arrives.

Sleep restriction therapy also works for some people who have insomnia. First, limit your night's sleep to 4 or 5 hours, then gradually add more sleep time each night until you achieve a more normal night's sleep. Daytime naps should be avoided during this sleep restriction therapy because napping may prolong insomnia by making it harder to fall asleep at night. In addition, during sleep restriction therapy, avoid driving a car or operating dangerous machinery until you have obtained adequate nighttime sleep.