There is clearly some root cause for her behavior. Presumably, she was not acting in this manner prior to marriage.
It would seem to be unusual if mental illness just happened to kick in after marriage. Same with drug use, its hard to imagine that she started taking drugs after marriage.
It may simply be the case that she has realized that marriage isn't the solution to her problems, and is acting out in response.
Having said that, its imperitive that you get out while you still can. Remove yourself, and deal with the consequences later.