I don't know if I actually buy this cause and effect. The writing and other hints sounded like some kind of neuroticism unrelated to sleep apnea. I wouldn't be surprised if it comes back in the future and the author "finds" some other cause such as eating gluten or anything else en repeat.
I don't think I have OSA, and I've always had poor sleep (ongoing), but going on allergy immunotherapy shots has tremendously improved my quality of life.