Delayed sleep phase type is defined as falling asleep and waking later than desired. Which option best describes it?

• A. Advanced sleep phase type
• B. Delayed sleep phase type
• C. Jet lag
• D. Insomnia

Answer: (B)

This is about circadian rhythm sleep-wake disorders, specifically delayed sleep phase type. In this pattern, the internal clock runs later, so both bedtime and wake time are shifted well after what is socially acceptable. People often sleep normally for their own schedule, but have great difficulty waking for early obligations because they’re naturally inclined to late nights and late mornings. It’s different from an advanced sleep phase type, which involves going to bed and waking earlier; jet lag is a temporary misalignment after crossing time zones; and insomnia is trouble initiating or maintaining sleep without a consistent pattern of a late sleep-wake schedule.