It's due to your mouth not having enough moisture most of the time. With some, usually pain killers, you can tell you have a dry mouth with others, it's not obvious but still takes a toll. I don't know where there's an exhaustive list anywhere but I've heard several treatments for chronic things like arthritis and antidepressants have the same effect without it being obvious until your teeth suddenly start to have problems when you never had problems before.
My Dentist Office Manager was reading a trade Journal about Meth and why it destroys teeth. In simple terms, Meth turns off the signal to your brain to produce saliva. Even though Saliva is unpleasant, it is the real, natural and only protector of your teeth.