Delayed Sleep Phase Disorder

Delayed sleep phase disorder is a circadian rhythm sleep condition in which a person's internal biological clock is shifted later than social norms require, so that sleep, alertness, body temperature, and hormone cycles all run on a delayed schedule; people with the condition are commonly described as natural night owls. Its hallmark is a persistent inability to fall asleep before very late at night, typically after midnight, that resists ordinary attempts to reset it, sometimes producing effects resembling severe jet lag or occasional insomnia. The disorder is usually lifelong once it persists past adolescence, and is more common in people with ADHD or a history of traumatic brain injury or long COVID. Management includes carefully timed light exposure, darkness in the evening, gradual shifting of bedtime, and medications such as melatonin or ramelteon.