This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Psychiatry
Deficiency of hypocretin leads to 
Select and explain. 
A. Somnambulism, B. Bruxism, C. Narcolepsy, D. Restless leg symdrome
C: Narcolepsy
Answer: C: Narcolepsy 
Explanation: Hypocretin is a neurotransmitter that promotes wakefulness and it's deficiency leads to Narcolepsy.