Narcolepsy Explained
A chronic neurological disorder of sleep-wake regulation, in the form that occurs without cataplexy
Narcolepsy is a chronic neurological disorder that affects the brain's ability to regulate sleep and wakefulness. Clinicians divide it into two types. Type 1 involves cataplexy, sudden brief muscle weakness triggered by strong emotion such as laughter or surprise, and is associated with a deficiency of the neurotransmitter hypocretin. Type 2 is narcolepsy without cataplexy, and hypocretin levels are typically normal. Both types share excessive daytime sleepiness as the central symptom. This page describes type 2. Diagnosis is made with overnight polysomnography followed by a next-day multiple sleep latency test, which measures how quickly a person falls asleep and whether they enter REM sleep unusually early.
Common Symptoms
Excessive daytime sleepiness
Sudden, hard-to-resist episodes of sleep during the day
Sleep paralysis
Vivid hallucinations while falling asleep or waking
Fragmented, frequently interrupted nighttime sleep
Unrefreshing sleep and naps
How Treatment Can Help
Modafinil is FDA-approved for the excessive daytime sleepiness of narcolepsy. It reduces sleepiness and helps people stay alert during the day. It treats the sleepiness only: it does not change the underlying disorder, it does not treat cataplexy, and the benefit ends when the medication stops.
Modafinil has risks and side effects. Review its safety information.
When to Seek Evaluation
Talk to a clinician if daytime sleepiness persists despite adequate nighttime sleep and interferes with your safety, work, or daily life. Our clinicians confirm and treat an existing diagnosis of narcolepsy type 2; we do not perform the sleep testing that establishes a diagnosis. If you have not been diagnosed, or if you experience sudden muscle weakness triggered by laughter, surprise, or anger, a sleep medicine specialist or neurologist is the right place to start.