I think we have to look at it as not only one thing or the other. There is a relationship between the anatomical stuff and the mental stuff. Some people have severe anatomical abnormalities and will need CPAP or surgery, no matter what is going on in their minds.
Other people will not get apnea no matter how much mental issues are going on, as their airways are quite clear. Of course, they can get other manifestations of TMS/MBS.
Some are in the middle.
Does that make sense?