Yes, DISASSOCIATION is a Scrabble word!

Letter values in Scrabble US: D 2, I 1, S 1, A 1, S 1, S 1, O 1, C 3, I 1, A 1, T 1, I 1, O 1, N 1.

Is it a valid word?

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

the state of being unconnected in memory or imagination
a state in which some integrated part of a person's life becomes separated from the rest of the personality and functions independently