A sleep disorder is a condition that disrupts sleep or interfers with sleep quality, often having a negative impact on daytime functioning or health. There are more than 80 sleep disorders identified in the International Classification of Sleep Disorders, and according to the National Sleep Foundation, more than 50 million Americans will suffer from a sleep disorder at some time in their lives. Some of these disorders are quite common. For example, the National Institute of Health estimates that 10% of the adult population of the United States suffers from insomnia, a condition that is characterized by difficulty falling asleep, difficulty staying asleep, or poor quality sleep. People with insomnia often report problems in cognitive function, such as impairment in attention, concentration, and memory. Problems in their personal and work relationships can also arise. They may be at greater risk for fatigue-related accidents and are more likely to suffer from psychiatric disorders like depression and anxiety. Sleep apnea, a sleep-related breathing disorder, is believed to affect between 4 - 7% of men and 2 - 5% of women. This disorder is of significance because people with untreated sleep apnea are at greater risk for hypertension (high blood pressure), cardiac arrhythmia (irregular heartbeats), stroke, and death.
The significant health consequences of sleep disorders have led experts to agree that these problems warrant medical attention.