Fun, but utterly lacking in balance
Okay, first off, this game is fun. I can't deny that.
However, as a game designer myself, I can't give it better than an average score because the cards are hopelessly unbalanced. The update helps slightly, but nonetheless, if the opponent's good cards are at the top of his deck, and yours are at the bottom, strategy doesn't factor in - you're just dead.
I like the sanity concept, although the different kinds you can get are also unbalanced. Some are almost meaningless, while others are game-destroying.
Make all the insanities bad, but not completely game-destroying, and up the sanity costs for the powerful cards until you'll think twice about casting them early! Add extra effects to the lame ones. Allow an option to skip your turn to discard and replace as many cards from your hand as you want. Etc...
You've got a good concept, now balance it out and make it a more strategic game!