Narcolepsy: Understanding Sudden Sleepiness and Sleep Attacks

Narcolepsy is a chronic neurological disorder of sleep-wake regulation caused by loss of hypocretin (orexin)-producing neurons in the hypothalamus. It affects ~1 in 2,000 people.

Core Symptoms (Tetrad)

1. Excessive Daytime Sleepiness (EDS): Irresistible sleep attacks, often in monotonous situations. Refreshing naps (10–20 min).
2. Cataplexy: Sudden bilateral muscle weakness triggered by strong emotions (laughter, surprise). Consciousness preserved. Pathognomonic for Narcolepsy Type 1.
3. Sleep Paralysis: Inability to move at sleep onset/offset. Often with hallucinations.
4. Hypnagogic/Hypnopompic Hallucinations: Vivid, often frightening sensory experiences at sleep-wake transitions.

Additional Features

• Fragmented nighttime sleep, vivid dreams, automatic behaviors.
• Obesity, increased metabolic rate.
• Onset typically 10–30 years; diagnostic delay averages 10+ years.

Diagnosis

• Polysomnography (PSG) + Multiple Sleep Latency Test (MSLT): mean sleep latency ≤8 min, ≥2 SOREMPs.
• CSF hypocretin-1 <110 pg/mL (Type 1).
• HLA DQB1*06:02 positive in 90%+ of Type 1.

Treatment

• Wake-Promoting: Modafinil, armodafinil, solriamfetol, pitolisant.
• Stimulants: Methylphenidate, amphetamines.
• Cataplexy: Sodium oxybate (night), venlafaxine, fluoxetine.
• Behavioral: Scheduled naps, sleep hygiene, avoid alcohol/sedatives.

Narcolepsy is manageable. Early diagnosis improves academic, occupational, and social outcomes.