What is delayed sleep phase syndrome?

Sleep Disorder: Delayed sleep phase syndrome refers to a disorder that results in individuals feeling sleepy at later times and waking up at later times. For example 3am to 11am. If truly delayed, these individuals have an internal brain clock that is not synchronized with our normal day/night light/dark cycle. They tend to feel sleepy in the early morning and awake when most people feel sleepy at night.

DSPS: Simply put, dsps is when a person can fall asleep and stay asleep normally (ie, insomnia is not an issue) but they habitually fall asleep late at night, such as 2-3 am. They also sleep a normal number of hours. Advanced sleep phase disorder is the exact same thing but the person sleeps early such as 7-8 pm. Think college student and elderly person respectively.

Delayed sleep phase: This is a sleep disorder in which you sleep predominantly during the day and stay awake late at night. Your sleep wake cycle has been delayed, it can be treated with chronotherapy in order to reset your your sleep point and wake point.