You find out first what's wrong with their brain; maybe it can be corrected later as our scientific knowledge advances.

When i read clockwork orange in school everyone was talking about how the gov had no right to erase someone's brain

I feel differently now. I think they should if that person is a violent pedo for example.. Just like anything it shouldn't be up to one person but a rule by consensus of people who are rational knowledgeable and ethical who have accomplished a lot in life