Insanity Defense in Criminal Cases

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 What Is a Criminal Defense?

In short, a criminal defense is a part of the criminal law process in which a person that has been accused of a crime builds a legal defense case that tends to disprove the accusations that they are being charged with. In other words, the purpose of criminal defense is to have the criminal charges being brought against a person lessened or dismissed outright.

The laws and regulations regarding criminal defenses fall under the umbrella of criminal law. Criminal law is the set of laws that address behaviors that are considered to be an offense against society, the state, or public. If a person is convicted of a crime that may be forced to pay criminal fines as punishment, or may also lose their freedom by being sentenced to either local jail or prison time.

Regardless of whether a person is being charged with a serious crime or a minor crime, the accused person still has the right to a trial, as well as certain other legal protections that are guaranteed to them by the American Constitution.

A person who is being accused and/or charged of committing a crime is known as a criminal defendant. It is important to note that every person that has been accused of a crime is presumed to be innocent until the government proves that they are guilty beyond a reasonable doubt.

In short, being found guilty beyond a reasonable doubt means that the fact finder must be certain of the criminal defendant’s guilt entirely, or the charges must be dropped. In other words, being found guilty beyond a reasonable doubt means that the state or federal prosecution has the burden of proof to convince the jury or judge that there is no other reasonable explanation that can come from the evidence presented by the prosecution at trial other than the defendant being guilty of the crime they are accused of.

However, an affirmative defense, also known as a legal defense, is a defense that may be raised by a criminal defendant which either excuses or justifies their criminal behavior. If the affirmative defense is successful, then that may either reduce the criminal charges being brought against the criminal defendant or prevent a criminal conviction entirely.

What Is the Insanity Defense?

The insanity defense is an affirmative defense that may be raised by a criminal defendant or their attorney which states that as a result of their being found legally insane, they lack the intent necessary to convict them of the crime that they are being accused of.

In other words, a criminal defendant who is found to be legally insane at the time that they committed the crime may be found not guilty, by reason of their insanity. This fact can be crucial when determining a criminal case due to the fact that even if the defendant committed the crime, because there was no general or specific intent for the crime to be committed, they may not be held liable for the cause.

Further, under specific circumstances, if the defendant is found guilty, the insanity defense can also serve as a mitigating factor in the criminal sentencing phase due to their mental impairment. This also applies to the affirmative defense of diminished capacity, which is further discussed below.

If the defense is able to establish that the defendant was legally insane at the time that the crime took place, their criminal behavior may be completely excused. It is important to note that upon finding instances of mental insanity, the court will generally order the defendant to be placed in a mental hospital for further evaluation and/or treatment.

This means that civil mental health commitment proceedings will often occur simultaneously with the criminal case. The defendant will first be found incompetent or insane in a court, and then the criminal charges brought against them will be dropped upon them being civilly committed to a designated mental health facility for a period of time.

Importantly, the elements necessary to prove insanity will depend on the state laws regarding insanity in the jurisdiction in which the crime occurred. Generally speaking, in order to establish a solid insanity defense, the defendant must satisfy at least one of the following tests, depending upon the jurisdiction in which the crime was committed:

  • The M’Naghten Test: According to the M’Naghten test, the criminal defendant either did not understand their actions’ nature and quality or lacked knowledge of the wrongfulness of their actions;
  • The Irresistible Impulse Test: According to the irresistible impulse test, the criminal defendant could not control their actions.
    • In other words, this test emphasizes the defendant’s volitional incapacity;
  • American Law Institute Test: The American Law Institute test proves that the criminal defendant lacked substantial capacity needed to understand the wrongfulness of their actions, or control them.
    • Here, a total lack of understanding or control is not required, but, instead, the defendant only must have been substantially unable to understand and/or control their actions;
  • The Durham Test: The Durham Test asserts that the criminal defendant would not have committed the crime “but for” their mental disease of insanity, of which their crime was a product.
    • With the exception of New Hampshire, this insanity test is not in use today; and
  • The Federal Test: The Federal Test states that as a result of several mental diseases, the criminal defendant could not understand the wrongfulness of their actions or they could not control their actions.

It is important to note that most state laws provide that the criminal defendant has the initial burden of providing evidence of legal insanity. This means that it is the responsibility of the defense to timely raise the affirmative defense of insanity.

Once again, insanity must be proven by a preponderance of the evidence. Once the insanity defense has been raised, some states then require the prosecution to prove beyond a reasonable doubt that the defendant was sane at the time they were alleged to have committed the criminal act.

What Is the Diminished Capacity Defense, and How Does it Differ from the Insanity Defense?

In addition to the insanity defense, some states also recognize a defense of diminished capacity, which is a mental defect that falls just short of insanity. Diminished capacity is not a complete legal defense, and generally only serves to mitigate a criminal defendant’s conviction to a lesser criminal charge. This is different from the insanity defense which serves as a complete defense to the charges being faced by the defendant.

In general, a criminal defendant can claim diminished capacity associated with a mental defect or associated with intoxication. In jurisdictions in which diminished capacity is recognized, diminished capacity can establish a defense for specific intent crimes.

How Do I Enter a Plea of “Not Guilty by Reason of Insanity?”

In order for a defendant to utilize the insanity defense they must raise the defense at the appropriate time during the criminal process. If they fail to timely raise the insanity defense, they may waive their ability to utilize the defense at a later point in the criminal process. Typically, the insanity defense is raised during the plea stage.

Pleading the insanity defense requires proving that the defendant was insane at time of the crime by a “preponderance of evidence.” This means that the criminal defendant must prove that it is more likely than not that they were insane at the time of the commission of the crime.

There are two ways in which to pursue an insanity defense:

  1. Plead both “not guilty,” and “not guilty by reason of insanity;” or
  2. Admit that they committed the crime, but plead “not guilty by reason of insanity.”

If the defendant is found to be guilty and the insanity defense was entered, the case will proceed to a sanity hearing which is called a “sanity trial.” A sanity hearing involves the same jury who made the original guilty verdict. During the sanity hearing, the defendant must prove the defense by presenting evidence such as:

  • Mental health documents which establish a history of mental illness;
  • The presentation of expert witnesses stating that the defendant was insane at the time of the offense; and
  • The presentation of hospital records which prove a history of mental illness and/or insanity.

In order to prove insanity in court, criminal defense attorneys must provide any and all evidence that their client’s mental illness prevented them from understanding the wrongness of their actions, or the nature of their conduct at the time of the criminal offense.

Do I Need an Attorney for Insanity Defenses?

If you or your loved one are facing criminal charges, and you believe that you or your loved one were insane at the time of the commission of the offense, then it is important to immediately consult with an experienced criminal defense lawyer.

A criminal defense attorney will be best suited to helping you understand your legal rights and protections according to your state’s specific criminal laws. Further, a criminal defense attorney will be able to help you understand whether or not raising the insanity defense is available in your case.

If so, an attorney will be able to timely raise the insanity defense to have the charges being brought lessened or dropped. Finally, an attorney can also represent you at any in person criminal proceedings.


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