New research links sleep deprivation to a large number of automobile and other accidents. Moreover, chronically sleep-deprived people are at higher risk for poor memories, mental illnesses, obesity, cardiovascular disease and early death. Yet today's 24/7 culture fights against the human body's biological need for about seven hours of sleep a night. Some people are especially sleep deprived, notably teenagers and late-shift workers such as police officers, nurses and medical residents. Meanwhile, some experts worry that overuse of sleeping medications is becoming a serious problem. Newer medications like Ambien and Lunesta are in some ways “safer” than older drugs, but they also affect brain function and sleep patterns in ways that are still not fully understood. With primary-care doctors now able to prescribe these medications because of their greater apparent safety, more people may get into trouble with sleeping pills.