Yes, AUTOMATISM is a Scrabble word!

Letter values in Scrabble US: A 1, U 1, T 1, O 1, M 3, A 1, T 1, I 1, S 1, M 3.

Is it a valid word?

AUTOMATISM is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

any reaction that occurs automatically without conscious thought or reflection (especially the undirected behavior seen in psychomotor epilepsy)