What are the Four Types of Insanity Defenses?

The insanity defense bridges mental health and criminal law, allowing people with severe mental illness to avoid regular punishment. U.S. law includes four main legal standards: the M'Naghten Rule, the Irresistible Impulse Test, the Durham Rule (Product Test), and the American Law Institute (ALI) Standards.

Each test focuses on different aspects of mental distress, including consciousness and volition, all of which rely on forensic psychiatrists. These experts examine and explain the defendant's mental condition and problems. The court determines whether the insanity plea will work. In 1843, following the trial of Daniel M'Naghten, the eponymous rule also asked: "Can the defendant's severe mental condition excuse the act?"

If a defendant did not understand what they were doing or lacked the understanding of right and wrong, they cannot be held criminally responsible. For this, a forensic psychiatrist plays a crucial role. In an insanity defense, a forensic psychiatrist must gather the accused's complete psychiatric history: previous diagnoses, treatment notes, and family mental health history. The individual undergoes a standard mental health examination. The interview assesses their reality, understanding, and thinking at the time of the crime.

They provide a professional perspective on whether the accused's mental illness caused them to fail to understand their actions and to see any moral or legal implications. A complete report prepared by a forensic psychiatrist combines clinical findings with the M'Naghten Rule and evidence in court, helping the judge or jury understand and decide difficult psychiatric concepts. Let's understand the four types of insanity defenses.

What are the types of insanity defenses?

People who have been diagnosed by a neurologist or board-certified psychiatrist with a major mental disorder or psychiatric illness that impairs their ability to control or understand their actions can use the legal term "not guilty by reason of insanity" as a defense.

Conditions which may qualify for a not guilty by reason of insanity diagnosis include:

• Schizophrenia with Psychosis
• Manic Episodes with Psychosis
• Postpartum Psychosis
• Acute Delirium
• Moderate to Severe Dementia
• Proven Seizures
• Moderate to Severe Neurocognitive Disorders
• Medication-Induced Psychosis
• Brain Tumor or Abscess

Furthermore, the insanity defense in criminal law is important because it shows a link between mental health and legal responsibility. People with certain mental conditions can use these defenses to avoid criminal punishment. Courts routinely use the following legal standards to determine whether to accept an insanity plea:

• M'Naghten Rule:

This law focuses on the cognitive aspect of mental illness, not control. The M'Naghton Rule is named after the 1843 case of Daniel M'Naghton. He was accused of murdering Edward Drummond because he believed Drummond was about to kill British Prime Minister Sir Robert Peel. Mr. M'Naghton was mentally ill and, at the time of the crime, was unable to understand or recognize that what he was doing was wrong.

The court case set the legal standard for the M'Naghton Rule, the test for a plea of ​​insanity in criminal law. The rule states that if, due to a severe mental illness, a person:

• Did not know what they were doing, or
• Did not know what was wrong. They could be acquitted of criminal responsibility.

According to the M'Naghten Rule, if a person either does not know what they are doing or is unable to distinguish between right and wrong due to a mental disorder, they should not be held responsible. This rule applies in most US states (Arizona, Georgia, Idaho, and Illinois).

• Irresistible Impulse Test:

Because of its limitations, the M'Naghten Rule led to the development of the Irresistible Impulse Test. It became clear that some people were profoundly mentally ill and knew their actions were wrong, but were unable to stop themselves.

The most famous example of the use of this test is the case of People v. Rogers (1886). In this case, Rogers was accused of murdering his wife. The defense claimed that due to a severe mental disorder, Rogers was unable to control his behavior, even though he knew what he was doing was wrong. Rogers had a history of mental health problems, and defense witnesses testified that he was experiencing a psychotic episode at the time of the crime.

The irresistible impulse test requires a court to accept a plea of ​​insanity when the accused's mental illness deprives him of the ability to resist the urge to commit a crime, even if the act is considered wrong. The general principle here is that the person retains the ability to act according to their rational thoughts.

• Durham's Law (Product Evaluation):

The Durham Rule arose from the 1954 court case of Durham v. United States, a landmark case in criminal law. Defendant John W. Durham was schizophrenic and had a history of mental health problems. He found himself in legal trouble when he was accused of breaking into a drugstore in Washington, D.C.

In court, Durham's lawyer argued that his client's actions were unplanned and were caused by his mental illness. He said he couldn't control what he did and wasn't aware of what he was doing when the crime occurred. Mental health experts argued that Durham acted because he was ill and couldn't follow the law.

The court's decision in this case led to the Durham Rule. It became the standard for pleading insanity. The court ruled that if a defendant's mental illness affected his actions, he could escape responsibility for his crime. This was a change from the earlier M'Naghton Rule, which only asked whether someone knew the difference between right and wrong at the time of committing the crime.

• The American Law Institute (ALI) Standard:

In 1923, the American Law Institute (ALI) began to make laws better and easier to understand. Then, in the late 1950s and early 1960s, they introduced the Model Penal Code (MPC) to improve the way criminal law works in the US. The biggest challenge? Detecting the insanity defense, which primarily involves mental illness and criminal responsibility, is incredibly difficult.

Changes to the MPC in 1962 led to the ALI Standards. Instead of trying to use a single test for insanity, they looked at the various problems with older rules like the M'Naghten Rule and the Durham Rule.

The ALI Standards examine whether someone understands what they did and can control themselves when determining whether they are legally responsible. Therefore, if a person has a mental disorder that prevents them from knowing what they did was wrong or from obeying the law, they are not held criminally responsible.

The Takeaway

The M'Naghten Rule and the Irresistible Impulse Test are common methods of determining legal insanity in the US. A court-ordered mental health exam of an insanity defense involves a close collaboration between a forensic psychiatrist and a judge. They attempt to distill what's going on in someone's mind into something that can be used in a courtroom.

A forensic psychiatrist's job is to provide an honest, clear picture of how the mind works, so everyone can see the truth. By evaluation of the defender through interview, reliable testing, and following good ethics, forensic evaluators help judges make decisions that protect personal liberty and the public's safety.

Ultimately, mental health evaluation in criminal defense cases, such as the insanity defense, is crucial to ensuring that justice is administered fairly and that defendants receive appropriate care, punishment for their crime, as well as attention for their mental health care needs.

Insanity defense cases rely heavily on mental health evidence. If you or a family member needs a court-ordered mental health assessment, consult with a forensic psychiatrist. For more information, visit https://gabapsychiatrist.com/insanity-defense/ or call +1(833)312-4222