Although much remains to be discoveredabout why human beingsneed sleep, an article published inNature in 2005 discussed the significantinsights researchers havemade over the past 50 years thatincrease the understanding of thefundamental nature of sleep. Oneimportant finding is that sleep maynot be a global phenomenon butrather a local phenomenon of thebrain. Another is that some sleepdisorders can be explained by thediscovery that wakefulness, non-rapid eye movement (REM) sleep,and REM sleep are not mutuallyexclusive states.
Because insomnia is the most prevalentsleep disorder, the researchersoffer some insights into hyperarousal,a condition common amonginsomniacs. These patients, who arein a constant state of hyperarousal,paradoxically may be less sleepy duringthe day, compared with individualswithout insomnia. Appropriatetreatment for this condition may bechronic administration of a sedativehypnoticagent, such as a benzodiazepine.The researchers noted thatthe risks of tolerance, abuse, anddependency that some associatewith chronic benzodiazepine administrationfor patients with well-documentedsleep disorders have beengreatly overestimated.