Sleep and wakefulness are behavioral and physiological activities. Sleep has been defined as a reversible behavioral state of perceptual disengagement from and unresponsiveness to the environment. It is a modified form of the basic rest activity cycle. According to the American Psychiatric Association, sleep disorders are major disturbances of normal sleep patterns that lead to distress and disrupt functioning during the day (APA, 2000). Not only are sleep disorders extremely common, affecting virtually everyone at some point in their lives, but they can also lead to serious stress and other...