II. Definitions
- Delayed Sleep Phase Disorder (Delayed Sleep-Wake Phase Disorder)
- Circadian rhythm disorder with late sleep onset as well as late wake-up time
- Results in excessive Daytime Sleepiness and Insomnia (difficulty initiating sleep)
III. Epidemiology
- Typically affects teens and young adults
- Prevalence: 7-16% of adolescents
- Onset in teen years with peak Incidence in early 20s
- Family History of Delayed Sleep Phase in 40% of patients
IV. Physiology
- Human clock is located within the suprachiasmatic nucleus (Hypothalamus)
- Regulates the circadian rhythm
- Most affected by light exposure
- Also impacted by meals, Exercise and other Activities of Daily Living
- Light exposure (media screens included) prior to bedtime inhibits Melatonin secretion
- Decreased Melatonin delays sleep onset
V. Symptoms
- Shifted sleep schedule by at least 2 hours later that typical acceptable times
- Persistent pattern for >3 months
- Patient has a "night owl" sleep pattern
- Difficulty initiating sleep (e.g. prior to 1-2 am)
- Difficulty waking up by typical awakening times (e.g. prior to noon)
- Provocative
- Evening light exposure
- Lack of morning light exposure
VI. Diagnostics
-
Sleep diary
- Keep diary for 7-14 days including weekends
- Log sleep times before and after intervention
-
Actigraphy monitoring for at least 1 week
- Accelerometer monitors patients overnight movement
- Calculates actual patient sleep time
VII. Diagnosis
- Late sleep onset with difficulty initiating sleep AND
- Late wake-up time AND
- Excessive Daytime Sleepiness and functional Impairments for at least 3 months
VIII. Management
- See Sleep Hygiene
- See Insomnia
- Overall strategy is to realign circadian rhythm and sleep-wake cycle to a school or work schedule
- Requires sticking to a schedule of bedtime and wake times
- Relies on good Sleep Hygiene
- Melatonin 3 to 5 mg orally at least 1.5 hours prior to desired bedtime
- Limit bright light exposure prior to bedtime
- Avoid computers, handheld devices, television watching before bed
- Bright Light Therapy on awakening
- Exposure to 2000 to 2500 lux for at least 30 minutes up to 1-2 hours after awakening
- Sunlight exposure during play or Exercise is even more effective
- Transitioning to optimal sleep timing
- Shift Melatonin/light exposure 1 hour earlier every 5-7 days until desired schedule is achieved
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Related Studies
| Concepts | Disease or Syndrome (T047) |
| Italian | Fase del sonno ritardata |
| Japanese | 遅延睡眠期, ﾁｴﾝｽｲﾐﾝｷ |
| Czech | Pozdní fáze spánku |
| English | Delayed sleep phase, delay phase sleep, delayed sleep phase |
| Hungarian | Késleltetett alvásfázis |
| Portuguese | Atraso de fase do sono |
| Spanish | Fase de sueño retrasada |
| Dutch | vertraagde slaapfase |
| French | Phase de sommeil retardée |
| German | verzoegerte Schlafphase |
