This week, the attorney for Andrea Yates, the Houston woman accused of killing her five children, announced he would probably seek an insanity defense for his client. Meanwhile, Texas Gov. Rick Perry vetoed legislation banning the execution of mentally retarded offenders. Does the law treat the insane differently than the retarded? And aren't all retarded people automatically protected by an insanity defense?
There is little legal connection between insanity and mental retardation. "Insanity" is a legal term, not a medical one. "Mental retardation" is a medical construct--generally applied to anyone who scores below about 70 on an IQ test. A defendant can be mentally retarded without being legally insane, and vice versa. Still, there is some overlap. Between 20 to 35 percent of all non-institutionalized mentally retarded people have also been diagnosed with some form of mental illness.
Evidence of mental retardation tends to be a factor at two limited phases of a criminal trial: during a preliminary competency hearing, and later--if the defendant proceeds to conviction--to mitigate the severity of the punishment.
Insanity, on the other hand, is a legal defense. Evidence of a defendant's insanity is put on during trial to support a specific legal theory for the defense: that the offender didn't understand what he was doing at the time of the crime. Courts have been clear that the insanity defense and competence to stand trial are wholly independent determinations because they involve a defendant's mental state at different times and because the ultimate questions differ.
The Competency Hearing
Court competency hearings determine whether or not a retarded defendant can: 1) comprehend the nature of the charges again him; and 2) assist in his own defense. If the defendant cannot do so, he will usually be committed to a forensic hospital or, under some state laws, to prison sometimes for life, depending on his crime. These hearings are conducted by judges who rely heavily on psychiatric reports.
An insane defendant may also go through a competency hearing prior to trial. But unlike a severely retarded offender, he may well be deemed competent to stand trial. Since retardation is a permanent condition while "insanity" may be treatable, the insane offender can be often be "made" competent, with medication or therapies, whereas the retarded defendant may not. In the case of Andrea Yates, her attorney suggested today that she is to be stabilized, or rendered competent, in order to plead insanity at trial.
The Insanity Plea
An insane defendant found competent to stand trial still has the option of pleading "not guilty by reason of insanity," a term which dates back to English common law. M'Naghten's Rule--still the test for legal insanity in about a third of the states--derives from an 1843 case involving a man who shot Prime Minister Robert Peel's secretary in the mistaken belief that the man was Peel. M'Naghten's rule holds that a person is insane if "at the time of committing the act, he was laboring under such a defect of reason from disease of the mind as not to know the nature and quality of the act he was doing, or if he did know it, that he did not know what he was doing was wrong." About half the states use a more lenient standard than this "right versus wrong" test to determine insanity, specifically whether "the defendant could have known of the criminality (wrongfulness) of his conduct or conform his conduct to the requirements of law." In Texas, where Andrea Yates' lawyer is contemplating using the insanity defense, the more stringent M'Naghten rule is used.
Most mentally retarded people are not found to be legally insane. Death penalty scholars believe that when President Bush recently announced in Europe that he opposes executing retarded offenders, he was confusing Texas' insanity test with the competency test.
While the public believes that some famous insanity pleaders, including the Unabomber, Lorena Bobbitt, and most notoriously, John Hinckley, "fake" insanity to avoid punishment, a 1991 study by the NIH showed that just under 1 percent of defendants pleaded not guilty by reason of insanity, and that only one in four of those pleas resulted in an acquittal. Even if a defendant can prevail on an insanity defense, she'll most likely be confined to a hospital for the severely mentally ill for a longer or equivalent period of time to her likely prison sentence.
Since the death penalty was reinstated in 1976, at least 35 mentally retarded defendants have been executed in the United States. In 1989, the Supreme Court ruled that it was OK to execute the mentally retarded because there was no "national consensus" against the practice. They have agreed to revisit that issue next term, in part because in 1989, only two states barred executing the mentally retarded. Today, 15 states prohibit it, with Gov. Jeb Bush in Florida having just signed such a bill last week.
Even if found competent to stand trial, a defendant has the right to bring in evidence of his mental retardation at the sentencing phase of the hearing. Juries can determine at that time whether an offender's mental retardation should be a mitigating factor in penalizing him.
Explainer thanks Professor Richard Bonnie at theUniversityofVirginialaw school.