Delayed Sleep-Wake Phase Disorder is characterized by

• A. Sleep earlier and wake earlier than desired.
• B. The disorder resolves without treatment.
• C. There is a tendency to stay awake late at night and have difficulty waking at conventional times.
• D. It is not a circadian rhythm disorder.

Answer: (C)

The key idea is a delayed alignment of the body's internal clock with the 24-hour day. In this pattern, the biological night starts and ends later than society expects, so the person naturally feels sleepy far after social norms and has real trouble waking up for early schedules. That leads to staying up late and finding it hard to wake at conventional times, causing daytime impairment and difficulty maintaining a typical work or school routine. This is a circadian rhythm sleep-wake disorder, not simply something that resolves on its own, and it’s distinct from sleeping earlier than desired, which would be a different condition. Management focuses on shifting the timing back toward the light-dark cycle, often with morning light therapy and/or timing of melatonin in the early evening to advance sleep, along with consistent sleep schedules.