II. Types: Extrinsic
III. Types: Intrinsic
-
Delayed Sleep Phase Disorder
- See Delayed Sleep Phase
- Late sleep onset as well as late wake-up time
- Results in excessive Daytime Sleepiness and Insomnia
- Advanced Sleep Phase Syndrome
- Sleepiness onset early in the evening (before 8 pm) with early awakening (by 3 am)
- Irregular Sleep-Wake Rhythm
- Sleep primarily occurs during multiple naps irregularly and inconsistently spaced throughout the day
- No primary sleep time occurs overnight
- Non-24-hour Sleep-Wake Syndrome
- Consistent circadian cycle of longer than a 24 hour day
- Results in gradually advancing sleep and wake times that progress each day
- For example, bedtimes advances from 10 pm to 11 to 12 to 1... until over a 3 week period, they return to a 10 pm bedtime
IV. Resources
- Wikipedia - Circadian Rhythm Sleep Disorder