You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is What is a feature of narcolepsy and explain in detail?
NarcolepsyThis is a disorder characterised by excessive daytime sleepiness, often disturbed night-time sleep and disturbances in the REM-sleep. The hallmark of this disorder is decreased REM latency, i.e. decreased latent period before the first REM period occurs. Normal REM latency is 90-100 minutes. In narcolepsy, REM-sleep usually occurs within 10 minutes of the onset of sleep. The common age of onset is 15-25 years, with usually a stable course throughout life. The prevalence rate of narcolepsy is about 4 per 10,000.The classic tetrad of symptoms is:i. Sleep attacks (most common):iii. Hypnagogic hallucinations:iv. Sleep paralysis (least common): Ref: A Sho Textbook of Psychiatry, Niraj Ahuja, 7th Edition, pg. no. 138