Insanity defence has always been a hot topic in the legal as well as psychological world. Basically, in an insanity defence case a defendant pleads “not guilty” on the grounds of having insufficient mental capacity at the time of the crime consequently challenging culpability.

This article explores the intricacies of insanity defence and discusses some of the infamous cases that captured public attention

Insanity Defence Cases

In 1843, in England, the UK court established the legal concept of the insanity defence following an attempted murder of the British Prime Minister by a man named Daniel M’Naghten. During the trial the jury discovered his crimes were an act of insanity. Therefore, the court acquitted him, leading to the formulation of the Mr. M’Naghten Rule. The M’Naghten rule was the first legal test for criminal insanity. It originated in England during the trial of Daniel M’Naghten. 

So, at the time of trial, M’Naghten’s counsel put forward a defence of insanity offering expert witness testimony and other evidence in support of this. Based on the evidence, the jury’s verdict was not guilty “by reason of insanity.”

 Due to this case, the following rules arose:

  • Presumably, every defendant is sane unless the contrary is proved;
  • To establish the defence of insanity it must be proved that at the time of committing the act the defendant was labouring under a defect of reason from a disease of the mind, not knowing the nature and quality of the act he was doing or if he did know he did not know the act was wrong.
  • The court presumes that every man knows the law of the land.
  • The entitlement to give an opinion lies with a suitably qualified expert.

Why did Insanity Defence become popularised?

The insanity defence gained popularity due to media attention and public fascination surrounding its use in high-profile cases involving individuals like John Hinckley Jr., Jeffrey Dahmer, and Ted Bundy. However, it is not utilised very often as only 1% percent of insanity defence cases see success. Nonetheless, questions about a defendant’s mental state during the offence occasionally arise in criminal trials or during plea negotiations. As the verdict of not guilty by reason of insanity (NGRI) and the insanity defence remain options it is crucial to comprehend the rationale, relevant legal issues and dispel common misconceptions.

Famous Insanity Defence Cases

Over the years, several high-profile cases involving insanity defence have captured the public’s attention. Here are four noteworthy examples:

Cases where insanity defence was a success

The Case of Andrea Yates

In 2001, Yates, a mother of five, drowned her children in a bathtub. During that year the police arrested Andrea and the court charged her with capital murder. She went on to plead not guilty by reason of insanity but the jury found her guilty and sentenced her to life in prison instead of the sought-after death penalty by the prosecutors. However, the court overturned her conviction later due to false testimony from a prosecution witness. The new development led to a grant for a new trial. In 2006,  the jury acquitted her by reason of insanity, and she went to a state mental hospital for rehabilitation.

John Hinckley Jr. and the Attempted Assassination 

When the verdict of “not guilty” for reason of insanity was delivered in 1982 on the trial of John Hinckley, Jr. for the attempted assassination of President Ronald Reagan people worldwide got outraged.  The motive behind the attempt was to impress actress Jodie Foster.  Hinckley’s lawyers argued that he was mentally unstable at the time of the shooting. 

This trial brought significant attention to the complexities of the insanity defence. It exemplified the challenges a jury faces when they are compelled to categorise a defendant as either “sane” or “insane,”.  Even though the defendant might fall somewhere in between on a spectrum. The Hinckley trial particularly underscored the difficulty of comprehending the thoughts and mental state of another human being.

Cases where insanity defence was a unsuccessful

Ted Bundy’s Trial and Sanity

Ted Bundy’s infamous killing spree shocked the nation, and his trial became a media sensation. In January 1976, authorities brought Ted Bundy to trial in Utah for his heinous crimes against women. After a highly publicised trial, the court sentenced him to death in 1979 for the murder of two college students.

Despite his previous convictions and impending death sentence, Bundy chose to relinquish control to a defence team during his final trial in January 1980 for the murder of Kimberly Leach. He pleaded not guilty by reason of insanity, likely considering it the only defence option remaining for him to try. Nevertheless, the pile of forensic evidence and eyewitness testimony linking him to the crime convinced the jury to return a guilty verdict again.

Jeffrey Dahmer’s Notorious Insanity Plea

In 1991, Dahmer’s despicable crimes shocked the world when he was arrested. Over a span of more than 13 years, he killed 17 men and boys without being apprehended. During the court proceedings, Dahmer asserted a plea of not guilty by reason of insanity. To declare him insane, at least 10 jurors needed to agree that he had a mental disease that either prevented him from distinguishing right from wrong or from controlling his actions. However, the jury never reached that point in the trial as they ruled that he did not suffer from a mental disease. The focus of the trial revolved around whether Dahmer could control himself.

Key Takeaways

In conclusion, the insanity defence has long been a subject of intense interest and debate in both the legal and psychological realms. Over the years, numerous high-profile cases have brought it into the spotlight, capturing public attention and fascination. The complexities surrounding the defence underscore the challenges in understanding a defendant’s mental state during the commission of a crime.

In such intricate legal situations, having the support of a qualified and experienced psychology expert witness can make all the difference in building a solid defence. At Concise Medico, we understand the critical role that expert testimony plays in an insanity defence case. Our company offers a certified panel of highly qualified psychology experts dedicated to providing excellent support and comprehensive insights for your legal team.

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