'You Can't See Why on an fMRI'

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

On the morning of June 20, 2001, Officer David Knapp responded to a 911 dispatch call in the Houston suburbs. A thin woman with long dark hair, fully dressed but inexplicably wet, answered the door. She was breathing heavily. The cop’s first glance into the house revealed no obvious crisis.
Knapp asked the woman why she had called the police. Her reply was the opening line in a long public drama that continued until the summer of 2006, when the woman, Andrea Yates, was acquitted by reason of insanity for the deed she announced to Knapp: “I just killed my kids.”

The corpses of four of Yates’ five children—ages 5, 3, 2, and 6 months—were in the master bedroom, scrupulously covered in burgundy cotton sheets. The corpse of her oldest child, 7-year-old Noah, was still in the bathroom, floating face down in the bathtub. The tub was filled almost to the top with water, plus the vomit and excrement that had left the children’s bodies as their mother grabbed them, choked them, beat them, and shoved their heads under the water until their lungs burst and they died.

Homicide investigator Bob King, summoned to the murder scene a couple hours later, summed up this freakishly horrible case: “Something like this, you just got to wonder.” So did the courts, and so did we all. After five years and two trials with contradictory verdicts, we’re still wondering.
Within 24 hours of Knapp’s visit, Andrea Yates was America’s most infamous mother. Her ongoing saga was both soap opera and legal drama, with a fascinating backstory starring a fanatical traveling preacher, a hapless husband, a hopeless wife, heedless doctors making possibly fatal errors, and bizarre living conditions outside the ken of the middle-class viewers following along on Court TV.

Yates became a tragic figure to some, driven by unmanageable forces of faith, family, and madness. Her acts were so difficult to understand that insanity seemed the only sane explanation. Yet while virtually everyone was horrified by her crimes, some women could also examine their hearts and circumstances, and wonder. As Newsweek columnist Anna Quindlen wrote right after the murders: “Every mother I’ve asked about the Yates case has the same reaction. She’s appalled; she’s aghast. And then she gets this look. And the look says at some forbidden level she understands.”

The public reaction to the Yates case combined an insistence on blaming a mentally ill Other with a clandestine understanding that human passions cover a wider range than we like to admit. Such mixed feelings underlie the medical concept of mental illness and the legal concept of insanity, both of which allow us to categorize and explain that which we cannot, or do not want to, understand.

By testifying in trials as expert witnesses, mental health professionals help us reclassify complicated moral and legal questions as seemingly clear-cut scientific matters. An endless stream of news stories about the latest advances in brain scans and the chemical conquest of personality enhances the experts’ credibility and feeds into a belief that we have come to a sophisticated understanding of the intersection between mind, brain, and behavior.

But a close look at Andrea Yates’ legal saga, along with a less-famous Supreme Court decision about the insanity defense that was handed down shortly before she was acquitted, casts doubt on the scientific validity and legal relevance of psychiatric testimony. Despite all those popular accounts of high-tech tools for understanding the mind, the real role of psychiatry in the courts is far from objective and unimpeachable. It amounts to adding yet another debatable perspective to an already fuzzy scene.

The Insanity Defense: Rare and Well Done?
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.

Yates dragged the insanity defense back into the headlines when she returned to court last summer for a retrial. Her initial 2002 conviction for murdering three of her children—the state held off on trying her for the other two—was overturned because Park Dietz, a psychiatric expert witness who testified for the prosecution, said something on the stand that wasn’t true. He claimed that an episode of Law & Order (a show for which he consulted, and of which Yates was a fan) featured a woman who drowned her kids and got off with an insanity plea. The implication was that Yates had gotten the idea for her defense from the show. But no such episode existed.

In January 2005 a state appeals court, concluding that Dietz’s error might have affected the jury’s decision, overturned Yates’ conviction. In her second trial, with a similar set of psychiatric professionals making similar arguments for and against her, she was acquitted last July by reason of insanity. Then Yates, officially guilty of no crime, was locked up in the maximum-security North Texas State Hospital at Vernon. (In January she was moved to Kerrville State Hospital.)

Yates’ legal team sold a narrative about a woman suffering from a physical problem with her brain. That problem, they argued, was more responsible for her crimes than she was; it removed her from the normal human realms of choice and responsibility. We know about this alleged physical problem with her brain not because the experts actually analyzed that organ, but because of the things she has done and said, and the ways certain drugs seemed to affect her emotions and behavior.

Andrea Yates had a history, going back to 1999, of bizarre and disturbing behavior, from extended fasts to attempted suicides with pills and knives. Her husband, NASA engineer Rusty Yates, had taken her to a series of psychiatric institutes. A string of doctors had diagnosed her with postpartum depression and schizoaffective disorder, giving her a variety of antipsychotics and antidepressants. Some of the drugs seemed, at least for a while, to relieve the more obvious symptoms of mental disturbance, such as incessantly pumping her feet up and down and an almost catatonic lack of communication.

Yates’ actions and words on the day of the murder certainly don’t seem, from a common-sense perspective, to indicate that she was outside the realm of choice and morality. She waited for a small gap in her day after Rusty went to work and before her mother-in-law, who helped her with the kids, showed up; she committed the murders methodically; she summoned both her husband and the police to her home promptly afterward.

None of the mental illnesses with which Yates was alternately diagnosed seem to be a sufficient explanation for her actions. Very few people diagnosed with postpartum psychosis, schizophrenia, or major depression kill anyone, much less their own children. Something other than a disease seems necessary to explain her actions adequately. In the opinions of many expert witnesses, a sizable portion of the lay public, and the first jury, the most sensible candidate for that something was Andrea Yates’ choice, for whatever reason, to murder her five children. If so, many reasoned, she deserved the same treatment from the legal system as anyone else who made that choice, for whatever reason.

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