Yes, HYDROPHOBIAS is a Scrabble word!

Letter values in Scrabble US: H 4, Y 4, D 2, R 1, O 1, P 3, H 4, O 1, B 3, I 1, A 1, S 1.

Is it a valid word?

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

a symptom of rabies in humans consisting of an aversion to swallowing liquids
a morbid fear of water
an acute viral disease of the nervous system of warm-blooded animals (usually transmitted by the bite of a rabid animal); rabies is fatal if the virus reaches the brain