Narcolepsy is a neurological disorder that hinders the capacity to control the sleep-wake cycle. In contrast to normal sleep, REM sleep begins quite soon after the initiation of sleep in narcolepsy. This irregularity causes excessive daytime sleepiness. Patients feel the urge to nap during the day. It has two types: Type 1 is accompanied by cataplexy, a sudden loss of muscle tone, Type 2 is without cataplexy.