Disorders and disturbances of sleep are widespread and can have significant consequences for affected individuals as well as economic and other consequences for society . The US National Transportation Safety Board has , according to Dr. Charles Czeisler , member of the Institute of Medicine and Director of the Harvard University Medical School Division of Sleep Medicine at Brigham and Women 's Hospital , discovered that the leading cause ( 31 % ) of fatal-to-the-driver heavy truck crashes is fatigue related , ( though rarely associated directly with sleep disorders , such as sleep apnea ) , with drugs and alcohol as the number two cause ( 29 % ) . Sleep deprivation has also been a significant factor in dramatic accidents , such as the Exxon Valdez oil spill , the nuclear incidents at Chernobyl and Three Mile Island and the explosion of the space shuttle '' Challenger ''
Three Mile Island
Three Mile Island accident
Sleep medicine