When you are sleep deprived, the boundaries between sleep and wakefulness may often become blurred. Recently research has shown that state "dissociation" is more common that anyone previously suspected. State dissociation is defined as the presence of more than one vigilance state concurrently. Vigilance states are defines as awake, rapid eye movement (REM) sleep, and non-REM sleep. Forgetfullness and daydreaming may be examples of this, but also more bizarre and even criminal behaviors could be, as well. In addition, perhaps 20% of vehicle accidents are related to sleep deprivation. Check out the article.