"The man who gunned down five people at Northern Illinois University in a suicidal rampage became erratic after halting his medication and carried a shotgun to campus inside a guitar case, police said Friday."
Why do I not believe in the insanity defense? This tells you why. Even though I understand that stopping your medication is often part of the mental disease (having a brother with a formof schizophrenia--I know: Most people say he is saner than I am), who says that an insane person is NOT responsible for his criminal actions? Is that not INSULTING to people with mental disease, and does it not indicate that we should lock some of them up BEFORE they commit crimes (if they are so irresponsible as to not be responsible for what they do.
Read Thomas Szasz ("The Myth of Mental Illness"). I do not go as far as he does (he appears not to believe in the concept of "mental illness"). But he says more intelligent things about "mental illness" than any ten other "mental health professionals".
Psychiatrists (mainstream, even apart from Szasz) say that insanity is a LEGAL concept, and nonsense as a "mental health" term. I take them at their word. Insanity should NOT be a "legal defense".
Should we not be sending the message to people with mental problems that they ARE responsible for what they do (despite whatever mental problems a person might have? I think that is an important message to send to every person. Szasz regards the concept of "mental illness" as a way society "punishes" non-conformist behavior (in other words, sort of a 1984 kind of control over conduct, to ensure it is acceptable to the general society). You don't have to go that far to see the benefit of the concept that ALL people are responsible for what they do.
Yes, it is just as INSULTING to say that minorities or the poor are not responsible for what they do. We need to come around to the view that EVERYONE is responsible for his or her own actions, regardless of background or even mental illness. Eliminating "insanity" as a legal defense would be a big step in this direction.