Def: chronic (>3 months) major advance (>2-3 hrs) in sleep-wake timing vs desired or required schedule
Main sx: early morning (terminal) insomnia
Epidemiology
Prevalence <1%, possibly underreported since less disruptive than DSWPD
More common in older adults
Rare autosomal dominant familial forms with PER2 and CSNK1D mutations
Assoc with neurodevelopmental d/o: Smith-Magenis syndrome, ASD, chromosomal microdeletions
Pathophysiology
Inverse of DSWPD mechanisms
Excess early morning light, or heightened response to its phase-advancing effect
Inadequate evening light, or poor response to its phase-delaying effect
Familial case showed shortened circadian period of 23.3 hrs
Possibly stronger and earlier homeostatic sleep pressure
Assessment
Detailed hx plus ≥2 wks of sleep diary and actigraphy
Advanced DLMO and core body temp minimum may be seen in familial cases
PSG mainly to exclude other d/o, e.g. OSA causing evening sleepiness
REM-predominant OSA can cause early morning waking
Treatment: Multimodal
1. Behavioral
Regularly scheduled daytime activity
Avoid evening naps, counter with exercise
Encourage good sleep behavior
Avoid early morning light
2. Light therapy
Evening light exposure, consider indoor lighting
Bright light box useful when used correctly
AASM 2015: weak rec for evening light tx in ASWPD
Caution with photosensitizing drugs in the elderly
3. Melatonin
Morning melatonin has limited evidence and may cause daytime sedation
- Oxford Handbook of Sleep Medicine 2022