ICD-117A60–7A65	CIRCADIAN RHYTHM SLEEP-WAKE DISORDERS Circadian rhythm sleep-wake disorders
ICD-10F51.2	Nonorganic disorder of the sleep-wake schedule
DSM-5-TRG47.21	Circadian Rhythm Sleep-Wake Disorders, Delayed Sleep Phase Type

1. Definition and nosology

Circadian Rhythm Sleep-Wake Disorders (ICD-11: 7A60–7A65; DSM-5-TR: G47.21) — mismatch between the internal circadian rhythm and the external social and light schedule; resulting in insomnia and/or sleepiness.

Subtypes: Delayed Sleep-Wake Phase Disorder (DSWPD), Advanced Sleep-Wake Phase Disorder, Irregular Sleep-Wake Rhythm, Non-24-hour Sleep-Wake (in blind individuals), Shift Work Disorder, Jet Lag Disorder.

2. History

• In the 1960s, Aschoff J. — foundations of circadian biology.
• AASM (2015) — clinical practice guideline for circadian rhythm disorders.

3. Epidemiology

• DSWPD — 7–16% in adolescents and young adults.
• Shift Work Disorder — 10–30% of shift workers.
• Comorbidity: MDD, anxiety, bipolar, cardiovascular.

4. Aetiology and pathogenesis

• Endogenous circadian rhythm disorder (clock gene mutations rare — Familial Advanced Sleep Phase).
• Environment — light exposure, social schedule.
• In adolescents, DSWPD — pubertal hormonal changes.

5. Clinical features

• DSWPD — late sleep and wake times; mismatch with school/work; “night owl” pattern.
• Advanced — early sleep and wake times; in elderly.
• Irregular — sleep episodes scattered throughout the day; dementia, ID.
• Non-24-hour — in blind people; the circadian rhythm does not entrain to the external light signal.
• Shift Work — shift work; insomnia + daytime sleepiness.
• Jet Lag — transient, rapid time zone change.

6. Diagnosis

6.1 Unified diagnostic criteria

A. Mismatch between sleep-wake schedule and internal circadian rhythm.

B. Insomnia, drowsiness, or both.

C. Duration ≥ 3 months (excluding jet lag and shift work).

D. Functional impairment.

6.2 Source-specific clarifications

• AASM 2015 Clinical Practice Guideline.

6.3 Diagnostic algorithm

1. Clinical interview + sleep diary for 1–2 weeks.
2. Actigraphy 2 weeks.
3. Dim Light Melatonin Onset (DLMO) — in research context.
4. Exclusion of comorbid sleep disorders.

6.4 Differential diagnosis

Insomnia, OSA, depressive disorder, narcolepsy.

7. Examination and assessment

• Sleep diary, actigraphy.
• Munich Chronotype Questionnaire.

8. Treatment

1. Bright light therapy — In DSWPD morning; in Advanced evening.
2. Exogenous melatonin — physiological low dose (0.3–5 mg); in DSWPD evening (time critical); in jet lag.
3. Chronotherapy — gradual shift of sleep timing.
4. Sleep hygiene and behavioral intervention.
5. Shift work — strategic resting, dark room, caffeine timing.
6. Non-24-hour in blind patients — tasimelteon (Hetlioz, FDA approved).

Treatment methods

1. Bright Light Therapy — 10,000 lux × 30–60 minutes; timing adjusted to the circadian shift.
2. Melatonin (Circadian) — Low dose; timing is critical.
3. Actigraphy — 2 weeks.
4. Tasimelteon — FDA approval for Non-24-hour.

9. Prognosis

With intervention, most patients improve; chronic form requires ongoing strategy.

10. Myths and misconceptions

Myth 1: “The adolescent is ‘lazy’ and can get up early”

Evidence: DSWPD is the neurobiological basis of circadian delay during puberty.

Myth 2: “Melatonin is a sleep medication”

Evidence: melatonin regulates circadian phase, hypnotic effect is minimal; timing selection is critical.

Myth 3: “There is no treatment for shift work insomnia”

Evidence: Strategic rest, light therapy, melatonin, caffeine timing improves.

Myth 4: “Jet lag resolves on its own”

Evidence: 1 day approximately for 1 hour of shift; acceleration with light + melatonin.

11. Sources

1. WHO. ICD-11. 7A60–7A65 Circadian rhythm sleep-wake disorders. 2024.
2. APA. DSM-5-TR. 2022.
3. Auger R.R. et al. AASM Clinical Practice Guideline for the Treatment of Intrinsic Circadian Rhythm Sleep-Wake Disorders. J Clin Sleep Med 2015;11(10):1199–1236.