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The Insanity Defense in a Criminal Case

If you’ve watched enough law movies and drama shows, chances are you have at some point seen a character plead insanity as a defense. According to a PBS article, less than 1 percent of county court cases involve the insanity defense, and that of those, only around one in four were successful. Despite this statistic, there are instances when this defense is successful. The first successful attempt at this defense was in 1843 when an Englishman shot and killed the secretary of the British Prime Minister, believing that the Prime Minister was conspiring against him. More recently, a teenager in Iowa was found not guilty of murder by reason of insanity in the death of his 5-year-old foster brother. So what exactly determines “insanity”?

First, the defendant must prove that he did not have control over his conduct similar to sleepwalking or being in a state of hypnosis. Secondly, the defendant does not have the ability to form criminal intent. They have no understanding of conduct that is “evil” or considered wrong by society’s standards. For example, if someone commits a crime and then tries to purposely mislead officers, they demonstrate an awareness that they did something wrong even if their behavior was mentally imbalanced. Due to these two factors in play, a defendant’s behavior is likely to be repeated again and again. As a result, there is no punishment or sentence that would rehabilitate the person. The only appropriate remedy is to treat their mental condition.

It is important to note that just with other areas of law, the insanity defense varies from state to state. Below are rules states use to define “insanity”:

The M’Naughten standard
In simple terms, this standard says at the time of the act, the person had a mental disease or defect that interfered with his ability to understand the nature and quality of the act he was performing or if he knew so, he did not know it was wrong.

Irresistible impulse
Focuses on the ability of the defendant to have control over his or her actions at the time of the crime.

The Durham rule
Focuses on whether the action was the result or product of mental disease or defect.

Some states acknowledge and follow one of these three rules but generally, use a combination of the three in their own interpretation. There are four states that have abolished the insanity defense: Idaho, Kansas, Montana, and Utah. Although the insanity defense is widely known, it is not properly understood by many and not nearly as used as one may think.

Under any test used, an insanity defense is going to require pre-trial motions and specific factual findings regarding medical conditions. A qualified criminal defense attorney can walk you through this process and let you know whether this is a workable defense. If you have any other questions about the insanity defense or need legal representation, get in touch with an experienced, local criminal defense attorney today.

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