Narcolepsy is a chronic disease of the central nervous system. Excessive daytime sleepiness (EDS) is the main symptom and is present in 100% of patients with narcolepsy. Other primary symptoms of narcolepsy include: • loss of muscle tone (cataplexy), • distorted perceptions (hypnagogic hallucinations), and • inability to move or speak (sleep paralysis). Additional symptoms include nighttime sleep disturbances and automatic behaviors (patients perform certain tasks without conscious awareness). All symptoms of narcolepsy can be present in various combinations and degrees of severity. Narcolepsy usually begins in adolescents or young adults and affects both sexes equally. The first symptom that appears is excessive daytime sleepiness, which can remain unrecognized for a long time as it develops gradually over time. Other symptoms may follow excessive daytime sleepiness for months or years. How common is narcolepsy? The prevalence of narcolepsy is similar to that of Parkinson's disease and multiple sclerosis. In the United States, the National Institute of Neurological Disorders and Stroke estimates that narcolepsy affects one in 3,000 people. Narcolepsy often remains undiagnosed or misdiagnosed for several years. This may occur because doctors do not consider the diagnosis of narcolepsy frequently enough. They might think of narcolepsy only in people whose main symptom is excessive daytime sleepiness. Narcolepsy may not be taken into consideration in the evaluation of patients who come to the doctor complaining of fatigue, tiredness or problems with concentration, attention, memory and performance, and other illnesses (seizures, mental illnesses, etc.). What are the causes of narcolepsy? Progress has been made in recent years in determining... half of the papers ...... and sleep paralysis), from the so-called "narcolepsy pentad" (a set of five symptoms). Automatic behavior can occur in 60% to 80% of narcolepsy patients. Automatic behavior occurs when patients perform certain actions without conscious awareness, often with the unusual use of words (irrelevant words, errors in speech). This behavior occurs as the patient fluctuates between sleep and wakefulness. Other disorders associated with narcolepsy may include eye problems due to drowsiness, such as blurred vision, double vision, and droopy eyelids. How is narcolepsy diagnosed? The diagnosis of narcolepsy is based on a clinical assessment, specific questionnaires, sleep logs or diaries, and sleep laboratory test results. Clinical evaluation Clinical evaluation includes a detailed medical history and physical examination by a doctor. Questionnaires