I am wondering how do doctors treat people with diseases like narcolepsy, sleep apnea or chronic fatigue?

Sleep apnea: Sleep apnea can be treated by losing weight, avoiding sleeping on one's back, wearing a device that forces oxygen into the lungs ( cpap) or a custom made dental device that holds the jaw forward to open the airway. Chronic fatigue may be related to sleep apnea, however, it might be a thyroid problem. Seeing an md for a proper diagnosis is essential to the proper care.

It varies.: For sleep apnea, the most common treatment is a pap device - it splints the airway open to prevent the repetitive airway blockage that fragments sleep. For narcolepsy, typically we utilize stimulant therapy and sometimes a medication called xyrem. It would be important to determine the correct diagnosis and then develop a treatment plan with your physician.