How The Insanity Defense Protects the Mentally Ill
As debates emerge as to the role of mental health in crime, we can turn to one of the longest-standing legal standards for cases involving mental illness. Since the 1800s, the insanity defense has assisted mentally ill defendants in avoiding imprisonment on the basis that they were clinically insane upon performing the crime. However, “not guilty” does not equate to being free. Defendants submit an NGI (not guilty by reason of insanity) plea and if they are found insane, they are sent to the custody of a psychiatric facility or mental health institution, frequently for a longer period than defendants sent to prison for the same offense. The insanity defense has only been raised in one percent of all felony cases, but the cases in which it has been drawn have significantly shaped the landscape for treating defendants with mental illnesses in the courtroom.
How the Courts Test Insanity
In the 19th century, most U.S. states assumed the defendant's insanity when they asserted an insanity defense. Courts initially required the prosecutor to prove beyond a reasonable doubt that the defendant was not insane. In 1982, when John W. Hinckley was acquitted of his attempted assassination of President Ronald Reagan after pleading insanity, many states began to shift their burden of proof. Public outrage at Hinckley’s defense had prompted states to reform their laws to assume sanity and to require defense attorneys to show, often by a preponderance of the evidence, that the defendant was insane. The laws to determine insanity vary by state but rely on applying a combination of four tests (the M’NAughten Rule, Irresistible Impulse Test, Durham Rule, and Model Penal Code), which assess an individual’s mental state and capacity to understand the nature of their actions or differentiate between right and wrong at the time of the alleged crime.
The insanity defense originated with the M'Naghten Rule test, which assumes all defendants are sane unless it is proven that the defendant did not understand their actions or know that their actions were morally wrong at the time of the crime. States often pair the M'Naghten Rule test with the Irresistible Impulse Test. Under the Irresistible Impulse Test, if the defendant provides compelling evidence that they suffered from a "mental disease or defect" that made it impossible for them to resist an impulse to commit a crime, they may be found not guilty by reason of insanity. The basis of the test rests on the defendant demonstrating that their mental illness caused them to lose control. Evidence from the prosecution that the defendant planned their crime or could control their actions invalidates this claim of insanity.
The Model Penal Code is an additional insanity defense test used to demonstrate that a defendant could not comprehend the criminal nature of their actions or was unable to "act within the confines of the law" because of a diagnosed mental disorder. Many states continue to use this test despite the widespread criticism it received after it was employed to acquit John Hinckley.
Finally, the Durham Rule finds a criminal defendant not guilty by reason of insanity if their "mental disease or defect" was the reason they committed a crime. Most jurisdictions deem the scope of the Durham Rule to be too broad; the rule is currently only utilized in New Hampshire.
Receiving Treatment through the Insanity Defense
The insanity defense received notable public interest in the case of Cody Metzker-Madson in 2014. Metzker-Madsen, a 17-year-old Iowa teen, was charged with first-degree murder in his 5-year-old foster brother's death. During Metzker-Madsen's trial, he testified he could see goblins fighting people he knew. He believed he was beating a goblin with a brick and shoving his head under the water, not his brother. The jury found Metzker-Madsen not guilty by reason of insanity, and the judge ordered him to stay at the Iowa Medical and Classification Center in the forensic psychiatric hospital unit. During his time at the medical facility, he was diagnosed with psychotic disorder, oppositional defiant disorder, and intermittent explosive disorder. At the medical center, Metzker-Madsen receives lifelong monitoring and treatment to limit the threat he can inflict on himself and the public. In this case, insanity outweighed guilt. Although the crime was heinous, because of the insanity defense, a teenager could receive treatment instead of being thrown into a prison system where their mental condition would worsen and compel them to harm again.
Is the Defense a Loophole for Criminals?
The insanity defense is often labeled as a loophole for criminals, but is that claim an extension of the stigma around mental health? Many doubt the depth of mental illness required in a defendant to validate an insanity defense. However, criminal law does recognize nuances in mental health and does not acquit based on the insanity defense for every mentally ill person.
Consider the 1979 trial of Dan White in which White was charged with first-degree murder after killing the city's mayor and supervisor. A psychiatrist for the defense testified that White's consumption of Twinkies and junk food weakened his mental capacity. The defense argued White suffered from depression, and the sugar from Twinkies exacerbated his poor mental state, driving him into a murderous frenzy. As a result, White was convicted of a lighter offense, involuntary manslaughter. White's team unconventionally employed the diminished capacity defense, a criminal law defense that a defendant should not be held fully criminally liable for their crime given their mental functions were impaired while committing the crime. White was found mentally ill but still fairly received punishment. The insanity defense was not manipulated to enable a sane criminal to walk free.
The insanity defense has a crucial role in preserving the rights of individuals grappling with severe mental illnesses within the legal system. By recognizing the unique challenges the mentally ill face, the defense diverts individuals from punitive measures and connects them to appropriate mental health interventions. Additionally, the defense provides a framework for assessing the management of mentally ill defendants in the courtroom. The insanity defense addresses the complex intersection of mental illness and criminal justice with compassion.