Insomnia

Description

Alternative Names

Prognosis

A 2002 study of sleeping habits in over one million people reported that people who slept seven hours a night enjoyed the longest lifespan. Those who slept 8 hours or more or 6 hours or less had higher mortality rates. People with insomnia did not have elevated mortality rates, which supported earlier evidence. People who took sleeping pills, however, did have lower survival rates.

Insomnia is virtually never lethal except in rare cases, such the genetic disorder called fatal familial insomnia. This rare degenerative brain disease develops in late adulthood. It is progressive and the individual develops intractable insomnia, which eventually becomes fatal.

Increased Risk for Accidents

As many as 200,000 automobile accidents in the US and 1,500 deaths from such accidents are caused by sleepiness. Studies continue to report that drowsy driving is as risky as drunk driving. In a major 2003 survey, 60% of young adults reported driving while drowsy and 20% dosed off while driving. In the study, 1% of adults who dozed off reported having an accident because of it. (One study strongly suggested that it was habitual sleepiness, however, and not just being sleepy at the time of an accident that places people at higher risk.)

Effect on Mood and Quality of Life

Surveys in 2001 and 2002 reported that people with severe insomnia had a quality of life that was almost as poor as in people with chronic conditions such as heart failure. In these studies, people with known depression or anxiety were not included. In addition to more daytime sleepiness, people with insomnia complained of more attention and memory problems compared to good sleepers. Insomniacs also experience more irritability, mistakes at work, and poorer relationships with their family than people who sleep well.

Effect on Thinking and Performance. Studies suggest that insomnia worsens many waking behaviors including the following:

• Reduced concentration. Some experts report that deep sleep deprivation impairs the brain's ability to process information.
• Impaired task performance. One study reported that missing only two to three hours of sleep every night for a week significantly impaired performance and mood. An Australian study reported that 17 hours of sleep deprivation causes impaired performance levels comparable to those found in people who have blood alcohol levels of 0.10%, a level that defines intoxication in many US states.
• Effect on learning. Whether insomnia significantly impairs learning is unclear. Some studies have reported problems in memorization, although others have found no differences in test scores between people with temporary sleep loss and those with full sleep.

Insomnia and Depression. Although stress and depression are major causes of insomnia, insomnia may also increase the activity of the hormones and pathways in the brain that can produce emotional problems. Even modest alterations in waking and sleeping patterns can have significant effects on a person's mood. Persistent insomnia may even predict the future development of emotional disorders in some cases. Some investigators, in fact, are exploring the possibility of preventing psychiatric disorders by early recognition and treatment of insomnia.

Alcohol and Substance Abuse

Although alcohol and substance abuse can cause insomnia, the conditions may be reversed. For example, a 1999 survey reported that 14% of American adults use alcohol within a month to help them sleep, with 2.5% reporting frequent use of alcohol to reduce sleep.

Effects on Physical Health

Effects on the Heart. Although there has been some concern that insomnia may increase the risk for heart problems, little evidence has supported any significant dangers. One study reported signs of heart and nervous system activity in people with chronic insomnia that might place such individuals at risk for coronary heart disease. If it exists, however, this increased danger is very modest compared with other risk factors for heart disease. Yet another report suggested that sleep complaints in elderly people without coronary artery disease predicted a first heart attack. Sleep disorders in such cases may have been a marker for depression, however, which is a risk factor for heart attacks in elderly people.

Effects on the Immune System. A 2003 study reported significant differences in immune factors among sleepers, with higher levels of certain infection-fighters observed in good sleepers than in people with chronic insomnia. The significance of these findings is still unknown, however.