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How Do You Prove Not Guilty by Reason of Insanity?

Key Takeaways:

  • An insanity defense means that a defendant is not guilty of the crime because they didn't have the mental capacity required to commit a crime.
  • If you are found not guilty by reason of insanity you could still be committed to a psychiatric institution.
  • The "insanity defense" is a difficult defense to prove, and is rarely successful in criminal trials.

The “insanity defense” is often used in movies and TV shows. It can make for a good story but the reality may be different. Claiming that you are not guilty by reason of insanity is one possible defense strategy you can use if you are facing criminal charges.

Your defense will rely on evidence proving that you were “insane” at the time of the alleged crime. A successful insanity defense means you are not criminally liable for breaking the law because you didn’t have the mental state (mens rea) required to commit the crime. This is different from lacking the competency to stand trial.

If you have questions about the insanity defense and how it can work in your case, talk to a criminal defense lawyer for advice.

What Is an Insanity Plea?

TV shows and movies portray defendants found not guilty by reason of insanity. In the criminal justice system, defendants are rarely successful with the insanity plea. According to one study, the insanity defense is only used in about 1% of all court cases. It is only successful in about 26% of those cases.

A defense of “temporary insanity” is difficult to prove. If a defendant asserts temporary insanity as a defense, they are claiming that:

  • They were legally insane at the time of the alleged crime
  • They are lawfully sane now

Most states use the M’Naghten Rule, sometimes called the right-wrong test. This involves mental defects that lead someone to believe in the rightness of their crime.

Other states use the Irresistible Impulse Test. This test reviews someone’s awareness and willpower that led to the crime. Other tests include the Model Penal Code Test (also called the substantial capacity test). This looks at a person’s lack of ability to follow the law or see that a crime is wrong.

New Hampshire is the only state to use the Durham Rule. This looks at mental defects (such as paranoia) that caused the criminal conduct.

If a court accepts the proof of temporary insanity and finds you not guilty, you are not likely to face time in a psychiatric facility. The temporary insanity defense is rare. It is typically used for circumstances where events leading up to the criminal act had a direct impact on the crime itself. Examples include:

  • Victims of emotional, sexual, or physical abuse
  • Family members seeking revenge for their victimized loved one
  • Victims of cults or other psychological tactics
  • People with unmedicated paranoid schizophrenia

In criminal law, the term “insanity” has a different meaning. It is not a medical definition of mental illness. You can have a mental disorder and be found guilty of committing a crime. You can also use the affirmative defense of insanity even if you have no history of mental illness or mental disease.

The definition of insanity also varies among different jurisdictions. To prove insanity, most jurisdictions require:

  • A professional assessment
  • Proof that you were not capable of distinguishing between right and wrong
  • Proof this mindset happened during the time of the offense (see temporary insanity below)

While the prosecution will have to prove your guilt beyond a reasonable doubt, the burden of proof will be on you to prove that you were “insane” at the time of the crime.

Some jurisdictions have an additional element for the defense of insanity. They allow a defendant to be found not guilty because of insanity if they were “unable to control their behavior at the time of the offense.”

What Happens If I Plead Insanity?

Most likely, you will need to have a complete mental evaluation as a first step when claiming insanity as a legal defense. Psychiatrists or psychologists can provide expert testimony. They will testify about your state of mind at the time of the offense.

However, even a professional alone can’t decide whether you are “insane.” It is up to a jury or judge to decide whether the professional’s testimony and other evidence support a finding of criminal insanity.

What Happens if the Court Finds Me Insane?

Criminal defendants can be committed to a psychiatric or mental hospital if they are found to be insane. You might not face prison time, but you could still spend just as much or more time confined in a psychiatric institution to protect public safety.

Civil commitment is generally not for a set amount of time. Defendants are committed until they are no longer a threat to society. Mental health doctors can make this decision on when to release a patient. You could also receive a conditional release and still have to receive treatment after release and be subject to oversight.

Insanity pleas allow for treatment instead of punishment for people who don’t have the mental capacity to stand trial. The insanity plea can offer rehabilitation and a second chance to offenders.

Using an insanity defense is something you should talk about with an experienced criminal defense attorney. An attorney will be able to examine your situation and help you determine whether this is a possible defense in your criminal case.

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