Editor BMJ, 1894. Various improvements have occurred throughout the century. It is now more difficult to overdose, although dependence has become an issue. Most people fall asleep when body temperature is going down. People most sleepy at body temperature minimum.
Deep sleep is the gateway to hibernation.
Research tends to show that if part of ritual and habit, then they may help. Costs millions to economies because of the development of alcoholism. To be read off to sleep by a gentle voice - this is the opening for radios, WEB radios, etc. Don't watch the TV if you have problems sleeping. Under development - 1999.