Aurora, Colorado movie theater shooter James Holmes has been found guilty of first-degree murder for killing 12 people and injuring 70 more in a 2012 spree.
Holmes had entered a plea of not guilty by reason of insanity. Reports the Denver Post:
The attack followed months of planning and preparation. In a notebook he later mailed to his former psychiatrist at the University of Colorado, Holmes described casing the theater before the shooting and strategizing for ways to keep victims from escaping.
Inside the theater he carried three firearms and hundreds of rounds of ammunition, most of it unused, prosecutors said, because his AR-15-style rifle jammed. He wore head-to-toe body armor, an outfit he later told psychiatrists was intended to keep him from getting hurt and also to make him look intimidating.
In writings and in conversations with psychiatrists after the shooting, Holmes said he committed the attack because he wanted to improve his "human capital" — a theory of his own invention that taking another's life would increase the value of his own.
In 2007, Brian Doherty wrote an in-depth analysis of the insanity defense as the retrial of Andrea Yates, who killed her five of her own children and claimed insanity, played out. Read "You Can't See Why on an fMRI." Here's a snippet:
When legal and psychiatric experts are asked about the insanity defense, they are apt to repeat wearily that it comes up in barely more than 1 percent of criminal cases and succeeds in only a quarter of those. They will also note that a verdict of "not guilty by reason of insanity" doesn't mean the criminal goes traipsing off scot-free, laughing maniacally to himself. In almost every case the "acquitted" defendant gets locked up, not in a jail but in a mental health facility. He'll stay there until some authority figure or body (depending on the state, it might be a judge or a board of psychiatric professionals) decides he is no longer a danger to the public. Defendants often spend more time locked up after "getting off" via the insanity defense than they would have if they'd been found guilty.
Despite the rarity of the defense, we talk about it a lot. In part that's because it makes for particularly colorful moral and legal drama, since it generally arises in cases where the crime seems to be beyond most normal people's ken. But it's also because the defense raises deep and eternally controversial questions about compulsion and free will.