[ Psychiatric ] Sleep Disorders 3

Narcolepsy: General definition

A chronic sleep disorder.

Narcolepsy: Core clinical characterization

Characterized by excessive daytime sleepiness (EDS) with inappropriate episodes of sleep.

Narcolepsy diagnostic criteria: Frequency and duration of sleep episodes

Recurrent episodes of irresistible need to sleep or daytime lapses into sleep occurring ≥3 times per week for ≥3 months.

Narcolepsy diagnostic criteria: Biomarker finding

Hypocretin (orexin) deficiency: low CSF hypocretin-1 levels.

Narcolepsy diagnostic criteria: Sleep study findings

Short REM latency on polysomnography / MSLT.

Narcolepsy (Cataplexy): Motor manifestation

Sudden bilateral loss of muscle tone.

Narcolepsy (Cataplexy): Common triggers

Triggered by strong emotions (laughter, anger).

Narcolepsy (Cataplexy): State of awareness

Consciousness is preserved.

Narcolepsy associated features: Motor inhibition description

Sleep paralysis: temporary inability to move at sleep onset or awakening.

Narcolepsy associated features: Hallucinations at sleep onset

Hypnagogic hallucinations (sleep onset).

Narcolepsy associated features: Hallucinations upon waking

Hypnopompic hallucinations (upon waking).

Narcolepsy non-pharmacologic treatment: Occupational and scheduling recommendations

Avoid shift work/irregular sleep schedule.

Sleep disorders categories: Category associated with drugs

Substance/medication-induced sleep disorder.

Circadian rhythm sleep-wake disorders: Core pathophysiology

Misalignment between the internal circadian clock and the external environment.

Circadian rhythm physiology: Natural cycle duration

Endogenous rhythm ≈ 24 hours.

Circadian rhythm physiology: Anatomical pacemaker location

Controlled by the suprachiasmatic nucleus (SCN) in the hypothalamus.

Circadian rhythm physiology: Primary external synchronizer

Light is the main environmental cue.

Circadian rhythm physiology: Free-running cycle without cues

Without light cues, rhythm may drift to ~25 hours.

Circadian rhythm sleep-wake disorders: Clinical symptomatic presentation

"Jet lag-like" symptoms (fatigue, poor concentration).

Circadian rhythm sleep-wake disorders treatment: Non-pharmacological modality

Bright light therapy (phototherapy): resets circadian clock.

Circadian rhythm sleep-wake disorders treatment: Hormone supplement modality

Melatonin: helps phase-shift sleep timing.

Restless legs syndrome: Core clinical manifestation

Urge to move the legs, usually with uncomfortable sensations.

Restless legs syndrome treatment: First-line pharmacotherapy

Dopamine agonists: 1st line.

Restless legs syndrome treatment: Mineral supplementation indication

Iron replacement if ferritin is low.

Restless legs syndrome treatment: General pharmacological precaution

Avoid exacerbating drugs