Sleep disorders pose a hazard to personal health, quality of living, and public safety.
The most commonly reported condition, insomnia, can adversely affect mood, efficiency, and relationships. Sleep deprivation plays as much a role in industrial accidents and traffic fatalities as drugs, alcohol, or equipment failure. The study of sleep and its disorders is a relatively young field. Most scientific study on sleep has been conducted in the past 40 years. Throughout human history, the subject of sleep has intrigued dramatasists, poets, artists, and philosophers.