It is important to keep in mind that deliverance from demons is only maintained through faithful obedience to the words of Jesus. Your sin opens the door. I had sleep paralysis. After I cast the demon out of myself, I have not had it return, of course, I am not perfect, but I faithfully seek the Lord and think on him everyday. I have also cast this demon out of others with the same results and out of others multiple times because they return to serve Satan.
People who think this is simply a chemical situation ignore my testimony and the testimony of others and their failure to believe keeps them bound.