Delayed sleep phase syndrome is the most common circadian disorder in adolescents and most adults with the condition report onset of symptoms during childhood or adolescence. Delayed Sleep Phase Syndrome involves a chronic mismatch between the usual daily schedule required by the individual's environment and his or her circadian sleep wake pattern. Individuals suffering from delayed Sleep Phase Syndrome experience great difficulty when attempting to fall asleep before 1-2 am, if not later, as well as rising at acceptable hours of the morning despite having completely normal sleep architecture and sleep duration. Delayed Sleep Phase Syndrome is a sleep disorder that results from a dysregulation of the circadian sleep-wake rhythm. Delayed Sleep Phase Syndrome is often the cause of severe insomnia and is associated with excessive daytime sleepiness, major depressive disorder and severe disruption of education, work and social functioning. Its major symptom is extreme difficulty initiating sleep at a conventional hour and waking on time in the morning for school or work.