Narcolepsy is a chronic neurological disorder characterized by the brain’s inability to properly regulate the sleep-wake cycle. People with narcolepsy experience excessive and overwhelming daytime sleepiness and may suddenly fall asleep at inappropriate times and places, regardless of how much sleep they had the previous night. It is a lifelong condition that can profoundly affect daily functioning, safety, and quality of life. The most distinctive feature of narcolepsy is cataplexy — a sudden loss of muscle tone triggered by strong emotions such as laughter, surprise, or anger. Cataplexy can range from brief muscle weakness (such as dropping an object or slumping) to a complete collapse of the body. Not all people with narcolepsy experience cataplexy; narcolepsy with cataplexy is classified as Type 1, while narcolepsy without cataplexy is classified as Type 2. Other hallmark symptoms of narcolepsy include sleep paralysis (a temporary inability to move when falling asleep or waking), hypnagogic or hypnopompic hallucinations (vivid, dream-like experiences at sleep onset or waking), disrupted nighttime sleep, and automatic behaviors (carrying out routine tasks while asleep without awareness or memory). Narcolepsy Type 1 is caused by a significant loss of neurons in the brain that produce hypocretin (also called orexin), a neurotransmitter that promotes wakefulness and regulates REM sleep. This loss is believed to be the result of an autoimmune process. While narcolepsy has no cure, symptoms can be effectively managed with a combination of medications (including stimulants for daytime sleepiness and antidepressants for cataplexy), scheduled naps, and lifestyle adaptations. Diagnosis is confirmed through sleep studies, including polysomnography and the Multiple Sleep Latency Test.