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The Insanity Defense in Criminal Law: A Comprehensive Exploration

Posted on in CrimeJanuary 23, 2024

The insanity defense is a contentious concept within criminal law, capturing public attention and sparking both legal and ethical debates. The crux of the argument is that defendants who lack the mental stability to differentiate right and wrong cannot be held fully responsible for their crimes.

Courts have sparingly accepted the insanity defense. However, criminal studies have found that less than one percent of US felony cases attempt to argue it with rare success. It's commonly deployed in desperation as a last resort.

Historical Evolution of the Insanity Defense

The insanity defense does not comply with a set standard, and the requirements evolve over time. This is partly due to our increased understanding of psychological illnesses but is also affected by cultural sympathies.

Claiming insanity as a criminal defense was first codified in British courts circa 1843. In an attempt to murder the prime minister, a Scottish woodcutter named Daniel M'Naghten accidentally killed the prime minister's secretary instead.

M'Naghten randomly blamed the prime minister for various problems in his life. His financial and personal woes had little to do with the prime minister's political career.

The jury decreed M'Naghten insane and acquitted him of the charges. The official verdict was recorded as "not guilty by reason of insanity."

Creation of the M'Naghten Test

The court's insanity verdict did not last long after reaching Queen Victoria's ears. She had the House of Lords, the British equivalent to the US Supreme Court, review the case and reverse the verdict.

This review led to the creation of the first standard of the insanity plea. The judges announced that the accused should not be held accountable if they could not tell their actions were wrong when the crime was committed.

Defendants must pass a series of requirements to be acceptably insane, but the judgments of these requirements are often subjective. This process is commonly known as the "M'Naghten Test."

Britain's governing of insanity cases quickly became the standard in American courts and persisted for over 100 years. However, new considerations were added that both broadened and narrowed the insanity defense over the years.

The Irresistible Impulse Test

Compared to the cognitive focus of the M'Naghten Test, the Irresistible Impulse Test introduced a different dimension to the insanity defense. Its primary purpose was to measure the defendant's ability to control their actions while considering how their mental disorders may hinder impulse control.

If the defendant was unable to stop themselves from committing the crime as a result of severe mental illness, they could be found not guilty through this test.

Many psychologists argued that insanity isn't only defined solely by mental competency. The M'Naghten Test only measured a person's ethical awareness, but not the inescapable physical effects of mental disease.

While unsuccessful, the first application of the Irresistible Impulse Test was in the Alabama Supreme Court case of Parsons v. State.

John Parsons was accused of murdering his wife, and his defense argued that he was insane during the incident. They stated that Parson's insanity was not caused by an inability to judge right and wrong but by an irresistible impulse to murder his wife,a situation reminiscent of cases of people with Multiple Personality Disorder

Although Parson's was found guilty of murder, it did cause the US court system to admit that the M'Naghten Rule's focus on personal decision-making did not account for severe mental illnesses.

The Durham Rule

The Durham Rule was created in support of the Irresistible Impulse Test. It was ultimately rejected as a standard but represented a more comprehensive consideration of mental health in criminal trials.

Established during the 1954 case of Durham v. United States, the Durham Rule relied on psychological experts to evaluate whether a mental illness unavoidably caused the accused's actions.

The practice was largely rejected as the courts realized that the field of psychology was largely unrestricted. There were very few academic standards to support the psychologist's findings, which caused the court's decisions to be equally unreliable.

The Substantial Capacity Test

The final standard for proving insanity to the courts is the Substantial Capacity Test, also called the Model Penal Code or ALI defense.

The Substantial Capacity Test combined aspects from the M'Naghten and Irresistible Impulse tests. It asserted that "A person is not responsible for criminal conduct if at the time of such conduct as a result of mental disease or defect he lacks substantial capacity either to appreciate the criminality of his conduct or to conform his conduct to the requirements of the law."

To meet these requirements, the defendant must have a mental illness that was triggered by the events leading up to the crime. While this test may sound like it requires a more rigorous burden of proof, it made proving insanity easier in the following ways:

  • The defendant must only lack a "substantial" capacity for knowing right from wrong as opposed to M'Naghten's standard of "total" loss of capacity.
  • The test only judges the defendant's mindset during criminal offenses rather than moral wrongs.
  • The defendant must only lack the ability to "appreciate" the law rather than "know" of it. This adds an emotional aspect to the proof that is easier to argue in court.

The Case of John Hinckley Jr.

Public sentiment, or indifference, toward the insanity plea, changed after the attempted assassination of Ronald Regan. In 1981, John Hinckley Jr. shot and wounded President Reagan along with multiple members of his security and entourage.

The attack was designed to impress famous actress Jodie Foster. Hinckley described the attack in a letter to the New Yorker in the following manner:

"The greatest love offering in the history of the world. At one time Miss Foster was a star and I was the insignificant fan. Now everything is changed. I am Napoleon and she is Josephine. I am Romeo and she is Juliet.

Hinckley was acquitted of 13 counts of assault and murder by reason of insanity. The surge of public pushback called for the complete upheaval of the American insanity plea, leading to the Comprehensive Crime Control Act.

Insanity Defense Reform Act of 1984

By 1984, the definition of insanity had become too complicated for the courts to decide reliably. The widely used Substantial Capacity Test could not determine whether a criminal act was legitimately uncontrollable or willfully uncontrolled.

Policymakers created the Insanity Defense Reform Act of 1984 to set stricter requirements to prove whether defendants could not control their actions. It eliminated several loopholes in definitional insanity, which allowed attorneys to apply the defense in unrelated situations.

The primary accomplishment of this act was changing the requirements from proving "reasonable doubt" to providing "clear and convincing evidence." This shifted the burden of proof onto the defense and made it much more challenging to avoid conviction with insanity.

Four states do not allow an insanity defense, including Montana, Utah, Kansas, and Idaho. While it is an option in the rest of the country, there are many reasons why less than 1 in 200 cases successfully argue it.

Requirements for Declaring Insanity in Court

Insanity in Court

Later, changes in the insanity defense require the defendant to have an appropriate mental illness. For the purposes of the law, insanity pleas preclude any conditions that only manifest with antisocial tendencies or illegal behavior. Some examples that have been successfully argued for include:

  • Autism Disorders
  • Post-Traumatic Stress Disorders
  • Schizophrenia
  • Major Depressive Disorder
  • Bipolar Disorder

Insanity defenses cannot be argued due to disorders resulting from voluntary intoxication or withdrawal from addictive substances.

The defendant must also have the "competency to stand trial" to declare insanity. This means that they must understand that they're under trial and be capable of assisting their defense. Many mental illnesses may prevent the accused from providing relevant or timely information.

If the accused is deemed not competent, the courts have two options. It may commit them to a mental institution or allow them to receive outpatient treatment. In the case of violent offenses, the former is typically chosen because it is closer to incarceration.

Role of Psychiatric Evaluation and Ethics in Proving Insanity

Pleading insanity requires concrete evidence. A large part of this evidence is a comprehensive psychiatric evaluation and testimony. The information gleaned from these professionals ultimately sways the court's decisions and influences justice's direction.

There's a lot of evidence supporting those who doubt the reliability of these evaluations. The results are often determined by the settings in which they occur, and the most significant contributing factors include:

  • Ideology, experience, and qualifications of the professional
  • Interviewing and investigation techniques employed
  • Completion of the evidence given to the professional

Ethical, Social, and Cultural Implications

The rarity and uniqueness of insanity cases often make them the focus of intense media scrutiny. The portrayal of individuals by the media will help shape public opinion and societal attitudes towards mental health.

For example, coverage can paint defendants in a more sympathetic light by highlighting the struggles and tribulations caused by their condition. Conversely, media outlets can turn sentiment against the defendant by downplaying the role of their illness in the crime.

Stigma and Mental Health Awareness

People are undoubtedly more conscientious of mental illness than in the past. The number of Americans receiving mental health treatment increased by roughly 50 percent in the past two decades.

However, this trend doesn't always apply to the most extreme cases. Insanity defense cases contribute greatly to ongoing dialogues surrounding mental health awareness. They help draw the line on acceptable behavior and what will be rallied against.

How a Country's Culture Impacts Insanity Defenses

Insanity defenses exist worldwide and are managed differently based on cultural differences. A country's perception of the impact and reach of mental illness heavily contributes to whether it allows insanity pleas.

For example, China heavily stigmatizes mental illness, which leads to psychiatric abuse and lacking medical access. Many people who would've had successful insanity pleas in the US could not escape capital punishment in China.

Those who successfully argue insanity in China are allowed a mitigated punishment but do not escape conviction altogether. The mitigation standard is generally consistent across the Asian Peninsula and it also exists in Japan, Korea, and Singapore.

The Insanity Defense is Still Evolving

Societal views significantly determine the evolution of the insanity defense. The more forgiving and sympathetic a populace is, the more likely policies will reflect that. The same also happens as our understanding of mental illness and treatment grows.

However, despite policymakers' best efforts, the insanity defense is still a somewhat nebulous concept. It relies on professional evaluations, which can vary between individuals. This has prompted many groups to speak out against the defense's viability while others espouse its necessity for protecting the little guy.

Undoubtedly, insanity pleas are a complex area of legal discourse and necessitate ongoing investigation to pursue justice and protect afflicted individuals.

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