Yes, CATATONIAS is a Scrabble word!

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

Is it a valid word?

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

extreme tonus; muscular rigidity; a common symptom in catatonic schizophrenia
a form of schizophrenia characterized by a tendency to remain in a fixed stuporous state for long periods; the catatonia may give way to short periods of extreme excitement

Also: catatonic schizophrenia, catatonic type schizophrenia.