That depends on why you're afraid to be open, and what power you are or think you are giving them. Beyond hospitalizing you after proving you're a threat to yourself or others, they can't force you to do anything. They have words, and if you mean your pdoc, they have a prescription pad, but you don't have to do anything you don't want. You still know they're supposed to help, or you wouldn't be asking this question.
I guess just ask yourself what you have to lose by being open vs not being open, and what you have to gain by being open vs not being open.