I don't think the mental illness of Joyce Brown is quite the same as those of the perpetrators of mass murder. The ones who commit mass murder for the most part seem reasonably normal to a reasonable person. Locking up the Joyce Brown's of the world will do no more to prevent gun violence than stricter gun control laws will.
If there is a solution to this problem it's beyond human comprehension. I can guarantee you one thing however. The solution certainly won't come out of Washington, any state capitol or town hall. I can guarantee you something else also. Whenever a tragedy like this occurs there will be a lot of grieving people left behind and significantly more who will capitalize off it for economic or political benefit.