By people, do you mean the prison guards, during the incarceration? I don't see any viable way to enforce medication after the end of a sentence.
Maybe if I had more faith in medication as a long term and lasting solution to psychological issues, I could see it working, but the mind is more complex than that. Chemical imbalances are interwoven with conscious attitudes and patterns of experience and history. That's not the sort of thing you can make go away with a convenient little pill. Even mandated therapy, like anger management classes, is questionable. Do the people who are forced to attend actually have any lasting changes in behavior, or are they just being warm bodies in a room, learning to give the answers that people are looking for?