Most people are familiar with the insanity defense as it receives a lot of attention in television shows and movies. Despite the exposure, the insanity defense isn't used that often and is successful in only a handful of cases. When a defendant asserts the insanity defense, he is basically stating that he isn't guilty because he wasn't able to understand that what he did was wrong. The idea is that someone shouldn't be punished if they don't know the difference between right and wrong.

Establishing Insanity as a Defense

What makes a valid insanity defense isn't the same in all states. The insanity defense generally requires that, at the time of the offense, the defendant, as a result of severe mental disease or defect, was unable to appreciate that his actions were wrong.

The defense requires a showing of severe mental disease or defect. This requirement prevents use of the insanity defense by those who have an immature personality or have displayed a pattern of anti-social behavior.

The defendant has the burden to prove the insanity defense by clear and convincing evidence. This means that the defendant must prove by clear and convincing evidence that due to severe mental disease or defect, he couldn't appreciate the nature and quality of his acts. This is a tough standard to meet and it helps assure that the defense isn't abused.

The prosecution doesn't have to show that the defendant was sane at the time of the crime because there is a presumption that the defendant wasn't insane. The defendant doesn't have to be permanently insane. The state of insanity can be temporary. The insanity must be brought about by factors that are beyond the defendant's control. Therefore, voluntary intoxication won't support an insanity defense.

Alleging Insanity Is an Admission

When the insanity defense is raised, it's an admission that the defendant performed all of the acts alleged by the prosecution. For this reason, if the jury rejects the insanity defense, the defendant will almost certainly be convicted.

When seeking to use the insanity defense, the defendant will have better chance of success if the illness is one that is recognized by the medical profession. Also, the jury will be more likely to believe the defendant if the illness was long standing, rather than a recently acquired illness.

Questions for Your Attorney

  • Does the law in my state recognize the insanity defense?
  • What is required to prove insanity in my state?
  • Have you ever successfully defended a case where a verdict of not guilty by reason of insanity was returned?