Advanced Sleep Phase Syndrome

Advanced Sleep Phase Syndrome (ASDS) is a sleep disorder in which patients feel very sleepy early in the evening (e.g. 18:00-19:00) and wake up very early in the night (e.g. midnight, 1:00, etc.).

It is opposite to Delayed Sleep Phase Syndrome.

ASPS is frequently encountered in the elderly and in post-menopausal women. It can be treated pharmacologically, with evening bright lights, or behaviorally with chronotherapy or free-running sleep.