[refresherd]

Much like sleep apnea in the morbidly obese, this is likely just a different condition entirely with a physical cause.

As to why it is prescribed anyways - like the MD who taught me about sleep apnea said, morbidly obese people get offended when you suggest that there aren't drugs that you can give them and they just need to take some extra weight off the strained organs. It's easier to give a person who is certain that it's not the weight, but some condition solvable with drugs, a drug.