Narcolepsy is a chronic neurological disorder involving the loss of the brain's ability to regulate sleep-wake cycles. Symptoms include excessive daytime sleepiness, comparable to how people who don't have narcolepsy feel after 24–48 hours of sleep deprivation, as well as disturbed sleep which often is confused with insomnia. Another common symptom of narcolepsy is cataplexy, a sudden and transient episode of muscle weakness accompanied by full conscious awareness, typically (though not necessarily) triggered by emotions such as laughing, crying, terror, etc. affecting roughly 70% of people who have narcolepsy.