Sleep disorders.

Humans spend approximately one third of their lives asleep. Although the same medical disorders that occur during wakefulness persist into sleep, there are many disorders that occur exclusively during sleep or are manifestations of a disturbance of normal sleep-wake physiology. The most common reason for referral to a sleep laboratory is OSA, whereas the most common sleep disorder is insomnia. Effective treatments now exist for many sleep disorders, such as OSA and RLS, and a major breakthrough in the treatment of narcolepsy seems imminent. Because all disease processes are adversely affected by insufficient sleep, it is essential that the practicing physician understand the causes and treatments of the common sleep disorders.