I am a thin guy with very low body fat. As soon as I told my doctor that I had woken up 2-3 times with my soft pallet dry & semi-collapsed, also that I would wake up regularly with a dry mouth, he immediately sent me for a sleep test. I went and did the test and the results were that I had mild sleep apnea. The sleep doctor told me that they were ordering a CPAP machine for me. I asked why I needed it for mild apnea and also told them I wouldn't use it. They ordered it anyway and told me to take the issue up with my doctor.
While all this was going on I was in the process of reducing the amount of meds I took (bad accident in 2010). I also started reading up on & studying sleep apnea. One of the first things I learned, and that worked, was keeping my mouth shut during sleep (many ways to accomplish that). The other thing I learned is that Big Pharma/FDA does a horrible job of listing medication side effects. I say that because "causes sleep apnea" was not on the list of side effects for carbamazeine (used for my peripheral neuropathy). As soon as I stopped the carbamazepine the apnea symptoms vanished. I have no need for a CPAP, it was ordered and I've received many calls about it, but there it sits at the sleep doctor's office..