Although much remains to be discovered about why human beings need sleep, an article published in Nature in 2005 discussed the significant insights researchers have made over the past 50 years that increase the understanding of the fundamental nature of sleep. One important finding is that sleep may not be a global phenomenon but rather a local phenomenon of the brain. Another is that some sleep disorders can be explained by the discovery that wakefulness, non- rapid eye movement (REM) sleep, and REM sleep are not mutually exclusive states.
Because insomnia is the most prevalent sleep disorder, the researchers offer some insights into hyperarousal, a condition common among insomniacs. These patients, who are in a constant state of hyperarousal, paradoxically may be less sleepy during the day, compared with individuals without insomnia. Appropriate treatment for this condition may be chronic administration of a sedativehypnotic agent, such as a benzodiazepine. The researchers noted that the risks of tolerance, abuse, and dependency that some associate with chronic benzodiazepine administration for patients with well-documented sleep disorders have been greatly overestimated.