If insomnia continues for more than a few nights running, it can become chronic and cause a sleep deficit that is extremely detrimental to the sufferer's well-being. Insomnia interrupts the natural sleep cycle, which can be hard to restore. Some insomniacs unwittingly perpetuate their complaint by napping in the late afternoon or early evening, leading to wakefulness at bedtime and more insomnia. Others push their bodies to the limits, until their sleep deficit causes severe physical and mental effects.

Many people who feel they are suffering from insomnia may actually have a lower physical need for sleep than they believe they do. A normal part of the ageing process is to sleep more lightly and for shorter periods of time, and some elderly people toss and turn in bed late at night or early in the morning when their body has no physical need for more rest, because they believe that they must 'need' a certain amount of sleep to be rested.

Insomnia is a common side-effect of some medications, and it can also be caused by stress, emotional upheaval, physical or mental illness, dietary allergy and poor sleep hygiene. Insomnia is a major symptom of mania in people with bipolar disorder, and it can also be a sign of hyper-thyroidism, depression, or other physical complaints with stimulating effects.

Additionally, a rare genetic condition can cause a prion based, permanent and eventually fatal form of insomnia called Fatal Familial Insomnia.

Cures for Insomnia
Many insomniacs rely on sleeping tablets and other sedatives to try to get some rest. Others use herbs such as valerian, chamomile, lavender, hops, and/or passion-flower.

Some traditional 'cures' for insomnia involve drinking warm milk before bedtime, taking a warm bath in the evening, exercising vigorously for half an hour in the afternoon, eating a large lunch, then a light evening meal at least three hours before bed, avoiding mentally stimulating activities in the evening hours, and paradoxically, making sure to get up early in the morning and to retire to bed at a reasonable hour.

Traditional Chinese medicine practitioners have been treating insomnia sufferers for thousands of years. A typical approach may utilize acupuncture, dietary and lifestyle analysis, herbology and other techniques, with the goal of rebalancing the body's energies to resolve the problem at a subtle level.

Although they seem unscientific, many of these 'cures' are sufficient to break the insomnia cycle without the need for sedatives and sleeping tablets. Warm milk contains high levels of tryptophan, a natural sedative. Lavender oil and other relaxing essential oils may also be used to help induce a state of restfulness.

The most commonly used class of hypnotics prescribed for insomnia are the benzodiazepines. This would include drugs such as diazepam, lorazepam, nitrazepam and midazolam.

Removing probable causes of insomnia:

• Avoid all caffeine if you can't sleep. Caffeine is responsible for most cases of insomnia, including insomnia in night-shift workers. Caffeine is found in coffee, tea, yerba maté (Ilex paraguaiensis), guarana, cocoa, kola nut (this includes all cola drinks); it is also found in "pep-me-up" sodas like Red Bull and similar, chocolate bars and other candy, and some people simply pop caffeine pills. Drink herbal teas or plain water instead of caffeine-containing liquids, and avoid the caffeine pills, too.
• The bedroom environment should be conducive to sleep. Some people are very sensitive to light while others are sensitive to noise. Keep your bedroom dark and quiet at night.
• Practice good sleep hygiene. Do not use the bed for too many activities besides sleep. Using the bed for reading, writing, watching TV and all sorts of other activities will lower your association of the bed with sleeping. Similarly, try to keep to a regular schedule of what time to go to bed and what time to wake up. Try not to sleep during the daytime.
• Sleep apnea can be a cause of insomnia. While a visit to the doctor will help in the diagnosis or ruling out of sleep apnea, a definitive answer will have to come from a study at a sleep lab.
• Sometimes lack of sleep is indicative of some emotional problem that's not being dealt with. If a person is not happy with their lifestyle, or they are putting off problems that should be dealt with, it can often result in sleeping trouble. Just as your body has nutritional requirements, everybody has social and environmental requirements. Sometimes, spending more time out with friends can help.
• Do you have depression? If you wake up too early and can't get back to sleep you might want to visit a doctor.
• Obscure allergies, such as dairy allergies, can sometimes cause sleeping disorders. Other symptoms may be very mild, such as slightly stuffed sinuses. A nutritionist can make helpful dietary and suppliment recommendations.

The subject of sleep deprivation was tackled in a most entertaining fashion by an episode of Star Trek ("Night Terrors" [TNG]). The crew of the USS Enterprise were caught in a spatial anomaly that prevented them from reaching REM sleep, the state at which human beings dream. REM sleep could be considered the essential part of the sleep state. It allows the subconscious to process all the information and the experiences that people receive each day. In other words, it "unclutters" the mind and allows us to completely relax. Without achieving REM sleep over a period of several consecutive days, humans may lose these abilities.