What Is the Irresistible Impulse Test? Everything You Need to Know

In some states, defendants can use the irresistible impulse test as a legal defense. California does not recognize it. California uses the M'Naghten test for insanity (Penal Code 25(b)), so this post explains the irresistible impulse test as background. Under the irresistible impulse test, the defense may contend that the defendant was unable to weigh the implications of their actions because they were driven by an overwhelming desire or compulsion to commit a crime.

What Is the Irresistible Impulse Test?

One element of numerous tests for the legal insanity defense is the irresistible impulse test. According to this ruling, even if the defendant understood that the criminal act they committed was illegal or immoral, they can still be found not guilty if they can demonstrate that their mental illness prevented them from controlling their impulses at the time of the crime.

This test was created in response to objections raised against the M'Naghten Rule. Numerous academics contended that the concept of insanity had to encompass more than just mental disorders.

The irresistible impulse test, in contrast to the M'Naghten Rule, looks at more than just a defendant's ability to decipher between what's right and wrong. It assesses their ability to control impulses that lead to illegal behavior. Therefore, if a defendant claims they were unable to control their actions, there are certain requirements that need to be proved, which we'll look at later on.

Passing the Irresistible Impulse Test

In order to succeed in a case using this defense, the defendant must demonstrate that their drive to commit a criminal act overcame them to the point where they were unable to stop themselves. To accomplish this, the defendant will have to provide evidence of their mental illnesses as well as an explanation for why their conditions caused them to act criminally without thinking about the repercussions.

In California, this is not enough. Under Penal Code 25(b), a defendant must prove by a preponderance of the evidence that, because of a mental disease or defect, they could not know or understand the nature and quality of the act, or could not tell right from wrong. Loss of self-control alone is not a defense.

However, it's often quite challenging for criminal defendants to prevail in cases involving the irresistible impulse test. Criminal defense lawyers might use evidence already in existence to prove that the defendant didn't have control over their actions when committing the crime. In California, though, that evidence must fit the M'Naghten test. Attorneys can also help with questions like What is coercion in law?

How to Prove Irresistible Impulse

To successfully prove insanity and that the defendant has an irresistible impulse, the following requirements must be met:

• The defendant has a mental illness: Any defendant who wants to argue irresistible impulse needs to have a mental illness.
• There must be something that caused the defendant to not be able to control his or her actions: Secondly, there needs to be a link between the criminal act and the mental disease. Essentially, it must be proven that the mental illness caused the criminal act. It must be proved that the mental disease results in an inability to control their actions.

While this might seem straightforward, proving that someone lacked control over their actions can be challenging. Some common approaches include receiving opinions from mental health experts and medical evaluations.

The evidence needs to confirm the existence of a mental disease and its impact on the defendant's behavior. If any environmental factors may have triggered the condition, these should also be noted in the proof as well. Goss Law can advise on other questions like What is the best evidence rule in California?

What Is the Problem with the Irresistible Impulse Test?

Unfortunately, there are many flaws regarding the irresistible impulse test. Firstly, there are many individuals who feel that the definition of insanity is too subjective and wide. The criminal justice system's objectives of punishing offenders and discouraging future criminal activity may be compromised by the ease with which people with mental illnesses may be absolved of their criminal behavior.

Furthermore, the defense is also criticized for providing a way for defendants to get away with their crimes without being held accountable. The scientific validity of this defense is weakened by the possibility that some criminal defendants will inflate signs of mental illnesses in order to defend their illegal actions.

California has abolished the diminished capacity defense (Penal Code 25(a) and 28(b)). Evidence of a mental disease or defect can be used only on the question of whether the defendant actually formed the required intent (Penal Code 28(a)). That is different from an insanity defense.

How Did the Irresistible Impulse Test Get Introduced Into Criminal Law?

The irresistible impulse test was introduced into the justice system around the 19th century and introduced an entirely new perspective on criminal responsibility. Parsons v State was the case that put this legal concept on the map.

In Parsons v State, it was held that even though an individual is able to distinguish right from wrong, they may still be granted pardon from culpability if a mental disease or defect is present.

A mental condition might weaken one's ability to choose voluntarily between morally right and wrong behaviors. In Parsons v State, the court ruled that an individual might experience a compulsion caused by the "duress of such mental disease." The deep effects of a mental illness had completely destroyed the defendant's capacity for free will at the time of the alleged offense.

There was a link between the illegal behavior and the mental illness. This created a cause-and-effect relationship, with the offense being caused by the mental illness. It also acknowledged the impact mental illnesses had on a defendant's ability to make decisions.

Ultimately, the court found that if a person is legally insane, they can be found not guilty even if the defendant knew they were committing a crime.

Contact a Criminal Defense Attorney for Further Information

Overall, the irresistible impulse test is a very controversial topic when it comes to law. Some people love it, while others hate it. In California, however, it is not a defense. California uses the M'Naghten test under Penal Code 25(b), so a person who could not control their actions but knew what they were doing and that it was wrong cannot be found not guilty by reason of insanity on that basis alone.

Anyone considering an insanity defense should have a criminal defense lawyer on their side who can gather and present evidence regarding the defendant's mental illness to the court.

If you or a loved one is facing criminal charges and has a mental illness, contact Goss Law for a free consultation with attorney Blair Goss.