Narcolepsy

Narcolepsy is a chronic neurological disorder that affects the brain's ability to regulate sleep-wake cycles. It primarily involves the central nervous system, causing excessive daytime sleepiness and sudden episodes of sleep that can occur at inappropriate times. People with this condition often experience cataplexy, which is a sudden loss of muscle tone triggered by strong emotions. Other common symptoms include sleep paralysis and vivid hypnagogic hallucinations. These symptoms can significantly impact daily activities, work, and social interactions due to unpredictable sleep attacks and muscle weakness.

Narcolepsy is a disorder of REM sleep regulation characterized by excessive daytime sleepiness and abnormal manifestations of REM sleep such as cataplexy, sleep paralysis, and hypnagogic hallucinations. The core pathology involves the loss of hypothalamic neurons that produce orexin (hypocretin), a neuropeptide critical for maintaining wakefulness. This loss is often autoimmune in nature, with genetic predisposition linked to the HLA-DQB10602 allele. The condition leads to fragmented nocturnal sleep and intrusion of REM phenomena into wakefulness. It is clinically significant due to its impact on quality of life and increased risk of accidents from sudden sleep attacks.