What is insomnia?

Insomnia is a sleep disorder characterised by an inability to sleep and/or to remain asleep for a reasonable period during the night. Sufferers typically complain of being unable to close their eyes for more than a few minutes at a time, or of 'tossing and turning' through the night. 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.

Sleep is essential for mental and physical restoration. It is a cycle with two separate states: rapid eye movement (REM), the stage in which most dreaming occurs; and non-REM (NREM). Four stages of sleep take place during NREM: stage I, when the person passes from relaxed wakefulness; stage II, an early stage of light sleep; stages III and IV, which are increasing degrees of deep sleep. Most stage IV sleep (also called delta sleep), occurs in the first several hours of sleep. A period of REM sleep normally follows a period of NREM sleep.

Insomnia is not a disease. Insomnia is a symptom, not a stand-alone diagnosis. By definition, insomnia is "difficulty initiating or maintaining sleep, or both." Although most of us know what insomnia is and how we feel and perform after one or more sleepless nights, few seek medical advice. Many people remain unaware of the behavioral and medical options available to treat insomnia. 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. Primary insomnia is diagnosed if sleep should normally occur, and two possible influences are ruled out. The first influence is something external, like noise or bright light that hinders sleep. The second influence is any disorder, medication, or other substance that might be causing the sleep problem.

Insomnia is more common in women and older adults. People who are divorced, widowed, or separated are more likely to have the problem than those who are married, and it is more frequently reported by those with lower socioeconomic status. Short-term, or transient, insomnia is a common occurrence and usually lasts only a few days. Long-term, or chronic insomnia lasts more than three weeks and increases the risk for injuries in the home, at the workplace, and while driving because of daytime sleepiness and decreased concentration. Chronic insomnia can also lead to mood disorders like depression.

More information on insomnia