Narcolepsy is a long-term neurological sleep disorder that affects the brain’s control of sleeping and waking. It causes excessive daytime sleepiness and may cause sudden sleep episodes, muscle weakness triggered by emotion and unusual experiences around falling asleep or waking.
Main symptoms
- Excessive daytime sleepiness: an overwhelming need to sleep despite adequate time in bed.
- Sleep attacks: falling asleep unexpectedly for seconds or minutes.
- Cataplexy: sudden temporary muscle weakness triggered by laughter, excitement, surprise or anger while consciousness is preserved.
- Sleep paralysis: temporary inability to move or speak while falling asleep or waking.
- Dream-like hallucinations: vivid sights, sounds or sensations at the boundary between sleep and wakefulness.
- Disturbed night sleep: frequent waking even though daytime sleepiness is severe.
Not everyone has every symptom. Cataplexy can range from brief drooping of the eyelids or jaw to collapse. It should not automatically be assumed to be fainting or epilepsy.
Causes
Many people with narcolepsy type 1 have very low levels of hypocretin, also called orexin, a brain chemical that helps stabilize wakefulness. This is thought to result from an autoimmune process in genetically susceptible people. Narcolepsy type 2 occurs without cataplexy and its cause is less clear.
Read more about neurological conditions in Brain and Nervous System Health.
Diagnosis
Diagnosis is made by a sleep specialist. The assessment reviews sleep habits, medications, mental and physical health and other causes of sleepiness such as sleep deprivation, sleep apnea, thyroid disease, depression and epilepsy.
A sleep diary or activity monitor may be used before overnight polysomnography. A multiple sleep latency test the following day measures how quickly a person falls asleep and enters rapid eye movement sleep. In selected cases, cerebrospinal fluid hypocretin may be tested.
Treatment and daily management
There is no cure, but symptoms can often be controlled with a personalized plan. Helpful measures may include:
- regular sleep and wake times
- planned short daytime naps
- consistent exercise and avoidance of heavy meals or alcohol before activities requiring alertness
- adjustments at school, university or work
- medication to improve wakefulness or reduce cataplexy and related symptoms
Medications require specialist review because benefits, side effects, pregnancy considerations and interactions differ. Some wake-promoting medications can reduce the effectiveness of hormonal contraception.
Driving and safety
Uncontrolled sleepiness can make driving, cycling, swimming alone, working at heights or operating machinery dangerous. Do not drive if you may fall asleep. Follow the legal notification and licensing rules in your country and discuss fitness to drive with the treating specialist.
Regular meals, burns prevention while cooking and telling trusted people how cataplexy looks can also improve safety.
When to seek medical advice
Arrange an assessment if you repeatedly fall asleep during the day, sleepiness affects daily life, or you have episodes of emotion-triggered weakness. Keep a record of symptoms, sleep and medications to support the assessment.
Seek urgent help for prolonged loss of consciousness, new one-sided weakness, a seizure lasting several minutes, serious injury during an episode or breathing difficulty. These are not typical symptoms to manage as narcolepsy without assessment.
Sources
- National Institute of Neurological Disorders and Stroke: Narcolepsy
- American Academy of Sleep Medicine: Narcolepsy
Reviewed: 28 August 2026
Medical disclaimer: This information is general and does not replace assessment or treatment by a sleep specialist or other qualified healthcare professional.