Whitman is a tad different case. During his autopsy they found a Brain Tumor. And depending where it is it can affect your thinking (sanity). Whitman's Brain Tumor 'likely' made him go off.
I suggested on a thread yesterday that Jared Loughner should have a PET Scan done. His lawyer should demand one to see if he has one.
(no excuse but could explain a lot).
Actually, it would be an excuse.
If it’s true Loughner was delusional (and if he wasn’t he spent the better part of three years putting on a very good act) he really wasn’t responsible for what he did.