I've just read an article about this, with references at the bottom.
corticalchauvinism.com/2016/05/18/bruxism-teeth-grinding-and-autism/
I have had issues with clenching all my life. I remember doing it as a child and I still do it every day and now have TMJ issues quite badly.
I really don't know how to stop. I've tried a mouth guard but cannot stand the feel of it in my mouth.
Anyone else struggle with this?