What science can, and can't, tell us about the insanity defense.

June 19, 2007 5:06 PM

'You Can't See Why on an fMRI.' Brian Doherty explores the vagaries of the insanity defense, centering on the sad cases of Andrea Yates and Eric Clark.
posted by Sticherbeast (7 comments total)

It's an interesting read, especially in this period, where neuroscience is being hijacked by pop psychology and pointless fMRI studies are written every day describing the general location of such abstractions as love, altruism, memory, and so on. I think people are very willing to believe something if it's even associated with modern science, which is why the insanity defense is tempting right now - you can show a slight abnormality based on a scan or exam, cherry pick the scientists' statements or examine them very carefully in court. Anything is an excuse, and as long as someone has a big, colorful brain diagram to make it look official, a layperson is going to be resistant to saying "Nah, that's probably irrelevant." Thanks for the links!
posted by BlackLeotardFront at 5:41 PM on June 19, 2007

That was interesting about incidence of violence in schizophrenics being the same as for the general populace. Can anyone here back that up?
posted by BrotherCaine at 7:47 PM on June 19, 2007

CONCLUSION: Data indicate a significant rate of minor and serious physical injury offences in former inpatients with schizophrenia. Moreover, results identify risk factors for future non-violent and violent criminal behavior in patients with schizophrenia.

See also, Understanding of the term "schizophrenia"by the British public.

note, I have not read these papers, just the abstracts [and only a cursory scan] - these were from the first two pages from a <schizophrenia violence> search on PubMed.
posted by porpoise at 7:54 PM on June 19, 2007

Well, it makes me feel better to hear that less than 1% of violent criminal court cases try to invoke the insanity plea. I don't think I'm alone in saying I'd long assumed it was MUCH higher.

It also makes me feel good that those who "get off" via the insanity plea still end up serving long(er) sentences in prison-like conditions, albeit in a way that benefits the guilty and the system alike.

When it was first suggested to me that those who plea insanity were basically "let off" I always used the analogy of someone peeing on my carpet at a party. If that happens - you're out. No questions. Someone might yell "but, dude, that guy's INSANE" - yeah, but... my rug is still soaked with urine.

(replace "urine soaked rug" with "dead relative", to match analogy to legal proceedings involving murder)
posted by revmitcz at 8:14 PM on June 19, 2007

A vivid illustration of how being found not guilty by reason of insanity could be worse than being found guilty is provided in One Flew Over the Cuckoo's Nest.
posted by girandole at 9:53 PM on June 19, 2007

This article made me angry.

I wonder if the author, who is so keen to dismiss expert psychological testimony in a context where it might help a defendant, is equally eager to get rid of it in all other legal contexts, especially those which aid the state in locking people up? As it stands now, some states allow sentences to be enhanced (including giving the death penalty) based on the juries' finding of "future dangerousness". This finding usually rests on the "expert" testimony of psychiatrists/psychologists to make those predictions. Even though these "expert" predictions have been found to be no better than flipping a coin, the Supreme Court held in Barefoot v. Estelle that it does not violate due process to allow that testimony in.

Expert psychological testimony is also key in deciding whether to civilly commit someone who because of mental illness is a danger to himself or others. It's also used in the increasingly frequent proceedings to detain sex offenders beyond their criminal sentences (which the Supreme Court also upheld in Kansas v. Hendricks).

On a more personal note, I just got off serving on a jury. I emphatically believe that if I had to evaluate the culpability of a defendant, I would want to know whether they were mentally ill or not, and what role that mental illness played in their conduct. I'm not sure why the author of this article thinks that "common sense" lay testimony on whether the defendant was operating under "delusions" is so superior to the testimony of an educated psychologist or psychiatrist. Those disciplines may not yet be completely objective sciences, but I find it hard to believe they have no value whatsoever.

In the end, I'm not sure what good it does society to throw severely mentally ill people in jail anyway. Call me crazy.
posted by footnote at 6:20 AM on June 20, 2007

Footnote, I think the primary driver of incarceration is fear, more than retribution or punishment, and certainly more than rehabilitation. In that sense, locking up crazy people serves the same purpose that locking up violent felons does. It removes them from society until they are weakened by age.
posted by BrotherCaine at 12:49 PM on June 21, 2007