Ninety-five percent of those are undiagnosed. Only within the past 25 years, have physicians become aware that the course of an illness might be altered by sleep or that some illnesses might manifest themselves only in sleep. Almost everyone, at some point in life, will experience some problem with sleep. An estimated one person out of ten has some degree of disturbed breathing in sleep. One out of five Americans reports that the quality or amount of their sleep is frequently or constantly unsatisfactory.
Many people complain about excessive daytime sleepiness.
More than a third of Americans complain about being unable to fall asleep or waking up during the night. This might be is a transient phenomenon. They too may have sleep apnea, narcolepsy or insomnia. Apnea patients are at a higher risk for stroke and cardiovascular disorders, particularly pulmonary and systemic hypertension and, congestive heart failure. Narcolepsy remains undiagnosed in perhaps half of all people suffering from it, and may be misdiagnosed as schizophrenia or Attention Deficit Disorder.