Yes, ALCOHOLISMS is a Scrabble word!

Letter values in Scrabble US: A 1, L 1, C 3, O 1, H 4, O 1, L 1, I 1, S 1, M 3, S 1.

Is it a valid word?

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

habitual intoxication; prolonged and excessive intake of alcoholic drinks leading to a breakdown in health and an addiction to alcohol such that abrupt deprivation leads to severe withdrawal symptoms
an intense persistent desire to drink alcoholic beverages to excess

Also: alcohol addiction.

Not playable in Scrabble US: POTOMANIA.