'You Can't See Why on an fMRI'

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

Brian Doherty from the July 2007 issue

(Page 3 of 4)

In June 2000, Clark, then 17, shot Jeff Moritz, a police officer who came to question him as he circled a residential street in Flagstaff in his pickup truck, blasting disturbingly loud music. Clark had told some acquaintances a few weeks earlier that he wanted to shoot some cops, which helped cast doubt on his later assertion that he thought he was shooting an alien rather than a police officer. Police found Clark later that day with gunpowder residue on his hands. They found the gun inside a knit cap near the scene of the shooting. In 2003, despite his insanity plea, he was convicted and sentenced to life in prison. (Curiously, Moritz’s father is himself a psychologist with experience in evaluating defendants’ competency to stand trial.)

Clark’s lawyers argued that Arizona’s insanity defense standard was so stringent that it violated their client’s right to due process. Under this standard, a defendant can be found “guilty except insane” (the phrase preferred in Arizona) if he did not realize his actions were wrong. He is then eligible to be confined in a psychiatric hospital rather than prison. Unlike the M’Naghten rule, the Arizona standard makes no explicit provision for a defendant who, because of a mental defect, did not “know the nature and quality” of his act. Without the other half of the M’Naghten rule, Clark’s lawyers insisted, Arizona’s insanity defense standard “offends [a] principle of justice so rooted in the traditions and conscience of our people as to be ranked as fundamental.”

That’s crazy, the Supreme Court said. In the first place, the “not knowing an action is wrong” part of M’Naghten that Arizona preserved really still includes the part about not knowing the “nature and quality” of the act. If you don’t know what you did, you obviously don’t know it’s wrong.
Besides, wrote Justice David Souter in the majority opinion, the history of the insanity defense shows that “no particular formulation [for the insanity defense] has evolved into a baseline for due process.” In fact, he said, the Due Process Clause does not even require a state to recognize an insanity defense. Four states—Kansas, Idaho, Utah, and Montana—technically do not, with the latter two having an alternate “guilty but mentally ill” category with little practical effect on the defendant if he’s found guilty. (One caustic legal scholar called it as meaningful as a “guilty but herpes” verdict.)

Clark’s lawyers also argued that the Arizona court violated their client’s right to due process by barring him from using professional testimony regarding mental illness to rebut the presumption of mens rea (that the accused acted knowingly and intentionally). The Supreme Court rejected that argument as well, and its reasoning in doing so undermines the basis for using psychiatric testimony at all. The Court noted that the “controversial character of some categories of mental disease, the potential of mental-disease evidence to mislead, and the danger of according greater certainty to capacity evidence than experts claim for it” give Arizona good cause to limit the areas where psychiatric testimony applies.

“The consequences of professional ferment,” the Court said, “is a general caution in treating psychological classifications as predicates for excusing otherwise criminal conduct.” In other words, psychiatrists disagree on diagnoses and their legal significance, to an extent that casts doubt on the objectivity of their science and its value for judges or juries. Clark’s original trial featured dueling psychiatric witnesses who agreed he was schizophrenic (one of the most wide-ranging and vague psychiatric classifications) but disagreed about what this diagnosis implied regarding his capacity to judge right and wrong.

The Supreme Court recognized that there is often no reason to believe a psychiatrist has any more knowledge on these legal and moral questions than a layman. “Empirical and conceptual problems” with psychiatry, Souter wrote, “add up to a real risk that an expert’s judgment in giving capacity evidence will come with an apparent authority that psychologists and psychiatrists do not claim to have.”

The case is too recent for us to have any clear notion of what long-term effects it will have on the practical nexus of psychiatry and law. Both the American Psychiatric Association and the American Psychological Association joined in an amicus brief asking the court to decide the case the other way. The Medill News Service reported after the decision that Dr. Paul Appelbaum, chair of the Counsel for Psychiatry and Law for the American Psychiatric Association and a former president of the organization, was bothered that, as the reporter put it, the “decision suggests that psychiatric expert testimony is less reliable than other forms of evidence” and thought that “the opinion seemed to reflect a bias against the field of mental health.”

On the legal front, Richard Bonnie, director of the Institute of Law, Psychiatry, and Public Policy at the University of Virginia, tells me that in his judgment when the Court discussed the merits of psychiatric testimony it was merely reaching for an excuse for the result it wanted to achieve—to uphold Arizona’s right to have its own policies on insanity and permitted evidence. It’s unlikely, he says, to have much effect on future jurisprudence.

Some law journal articles have already judged the court’s reasoning in Clark and found it wanting. In a monograph published by the University of Pennsylvania Law School, Stephen Morse (a law professor at Penn) and Morris B. Hoffman (a state district court judge in Colorado) declared that the court’s reasoning was confused about the distinctions between the insanity defense and mens rea and thus often dealt with issues the case didn’t really raise. Morse and Hoffman also tried to grapple with the meaning of modern neuroscience to the law, ultimately concluding that, from a legal perspective, “even if pure [neurological] mechanism is true…human beings will find it almost impossible not to treat themselves as rational, intentional agents unless there are major changes in the way our brains work. Indeed…there are powerful evolutionary explanations for the causal efficacy of our mental states [that make us think we have free will], states that are the predicates for responsibility. Overcoming what may in fact be neuro-architectural facts of evolution may be only a little less likely than ‘overcoming’ our opposable thumbs.”

Insanity vs. Free Will
As Morse and Hoffman recognized, the insanity defense is far from a simple legal issue. It is tangled with many controversial questions of science and philosophy. What is the relationship between mind and brain? Is there free will, such that any of us, sane or insane, are really responsible for what we do? Some neuroscientists and philosophers say the “free will” that appears to lie behind traditional legal notions of responsibility and blame is nonsense, that belief in it is as outmoded as belief in phlogiston or a flat Earth. Others counter than none of science’s interesting discoveries about how our brains work has enabled us to specify how an observable physical or chemical action in the brain equals (or dictates) a thought, an emotion, or an action.

The Harvard linguist and psychologist Steven Pinker, author of How the Mind Works, summarized the optimistic belief in what neuroscience teaches us (or will soon teach us), and why it is controversial, in the January 29 issue of Time. “Few scientists doubt that they will locate consciousness in the activity of the brain,” he wrote. “For many nonscientists, this is a terrifying prospect. Not only does it strangle the hope that we might survive the death of our bodies, but it also seems to undermine the notion that we are free agents responsible for our choices.”

Steven Faux, chairman of the psychology department at Drake University, wonders how much neuroscience tools have really done for us so far. An fMRI scan, for example, attempts to measure neuronal activity by detecting blood flow in the brain. But as Faux told Scientific American in 2005, “The beautiful graphics fMRI produces imply much more precision than there actually is. It’s really a very gross, if not vague, physiological measurement that people are using to try to pin down some very complex behaviors. And in too many studies the authors way overinterpret the data.” Critics of fMRIs, such as William Uttal, an emeritus professor of psychology at the University of Michigan, question whether brain function is compartmentalized enough for information about blood flow to tell us much, condemning the process as “the new phrenology.” Dr. Jay Giedd, chief of brain imaging in the child psychiatry branch at the National Institute of Mental Health, told The New York Times in 2005: “I have been waiting for my work in the lab to affect my job on the weekend, when I practice as a child psychiatrist. It hasn’t happened. In this field, every year you hear, ‘Oh, it’s more complicated than we thought.’ Well, you hear that for 10 years, and you start to see a pattern.”

The effects of psychiatric drugs likewise do not indicate that we have developed a clear picture of how brain activity is related to behavior. The Clinical Antipsychotic Trials of Intervention Effectiveness, the results of which were reported last year in The New England Journal of Medicine, found that even newer antipsychotics such as olanzapine (sold under the trade name Zyprexa) and risperidone (Risperdal) are not necessarily safe and effective for most patients. In the 18-month study, nearly three-fourths of the patients refused to keep taking the drugs because they didn’t work or had intolerable side effects, including slurred speech, loss of coordination, insomnia, and weight gain.

And when it comes to antidepressants, a 2002 study by the University of Connecticut psychologist Irving Kirsch found that, as Kirsch wrote in a Psychiatric Times summation of his research, “although the response to antidepressants was substantial, the response to inert placebo was almost as great. The mean difference was…not clinically significant.…More than half of the clinical trials sponsored by the pharmaceutical companies failed to find significant drug/placebo difference.”

Other studies have shown significant placebo effects for many physical ailments, from pain to high blood pressure, further limning the links between beliefs in the mind and what happens in our bodies. It seems reasonably clear that something arises as an emergent property of our brains’ matter in motion that can act on that matter. Chemicals in the brain obviously have a strong influence on the mental realms of choice and intention, as well as on the physical ones of behavior and action. Just ask anyone who has ever been drunk or high.