My Mother Is 56 And Has Always Had Periods Of

My mother is 56 and has always had periods of awful moodswings. The psychiatrist has always prescribed Olimelt tablets & after a few weeks of medication she usually recovers to her normal, jovial cheerful self.
Problem is, when she relapses into schizophrenia she becomes very aggressive, quarrelsome, rebellious and absolutely rejects any request to go to the doctor or take any medication.
I have to secretly administer her Olimelt in her food but she finds out and all hell breaks loose.

How do I go about it? This is an extremely painful time