Insanity Defence : A Loophole for Criminal

Posted On : February 24, 2022
Insanity Defence : A Loophole for Criminal
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The insanity is one of the unfavourable ranges of the law of crime. It is the war between the medical and legal profession, the insanity as a defence draws a deduction from the scant evidence, insanity is apparently a question of fact not gauged by inflexible legal test. A mentally ill person is not punished for his/her crime as she/he is devoid free will.

Insanity Defence or Plea is defined as, “The insanity defense refers to a defense that a defendant can plead in a criminal trial. In an insanity defense, the defendant admits the action, but asserts a lack of culpability based on mental illness”[i].

It is based on the assumption that at the time of the crime, the person was suffering from mental illness and hence was incapable of understanding what he/she was doing. It is to be noted here that this is a legal concept and simply suffering from a mental disorder is not sufficient to prove insanity.



Insanity defense has been in existence since many centuries; however, it took a legal position only since the last three centuries. There were various tests used to declare a person legally insane such as Wild Beast test, The Insane Delusion test, and test of capacity to distinguish between right and wrong. These three tests laid the foundation for the landmark Mc Naughten rule.

In 1843, Daniel Mc Naughten[ii], a wood-turner from Glasgow, shot and killed Edward Drummond mistaking him for Sir Robert Peel. Evidence was brought to show that he had been totally deluded on this subject for some time. After hearing seven medical witnesses testify that he was completely insane, the judge stopped the trial, the jury brought in the special verdict without summing up and without retiring, and Mc Naughten was forcibly committed to the Bethlem Hospital. It was laid that "Nothing is an offence which is done by a person who, at the time of doing it, by reason of unsoundness of mind, is incapable of knowing the nature of the act or that he is doing what is either wrong or contrary to the law."

This Mc Naughten rule became a legendary precedent for the law concerning the defense of insanity.




In the Nordic countries, insanity is not a defense. Instead, it is the responsibility of the court system as such to consider whether the accused may have been psychotic or suffering from other severe mental defects when perpetrating the criminal act. However, rules differ between Nordic countries.

In Sweden, they are seen as accountable, but the sanction is, if they are psychotic at the time of the trial, forensic mental care.

In Norway, "a person who at the time of the crime was insane or unconscious is not punished".[iii]

In Denmark, "Persons, who, at the time of the act, were irresponsible owing to mental illness or similar conditions or to a pronounced mental deficiency, are not punishable".[iv] This means that in Denmark, 'insanity' is a legal term rather than a medical term and that the court retains the authority to decide whether an accused person is irresponsible.


To establish a claim of mental disorder the party raising the issue must show on a balance of probabilities first that the person who committed the act was suffering from a "disease of the mind", and second, that at the time of the offence they were either

1) unable to appreciate the "nature and quality" of the act, or

2) did not know it was "wrong".

The meaning of the word "wrong" was determined in the Supreme Court case of R. v. Chaulk[v] which held that "wrong" was not restricted to "legally wrong" but to "morally wrong" as well.

An accused who is found to be unfit to stand trial is subject to the jurisdiction is referred to a Review Board to determine whether the accused is fit to stand trial. They must then determine what conditions should be imposed on the accused, considering both the protection of the public and the maintenance of the fitness of the accused.


Provision for Insanity Defence is given under Section 84 of IPC under “Act of person of unsound mind” which states that nothing is an offence if it is done by a person who, at the time of commission, because of unsoundness of mind, was incapable of understanding the nature and consequences of the act he/she is doing and also was unaware that the same is prohibited by law.

The provision is divided into two broad categories, first being Major criteria which cover cases where the person was suffering from mental illness during the crime and the Second being Minor criteria which cover cases:

Under both these criteria, the insanity is legal insanity and therefore once proven the accused could be acquitted.

It is also to be noted here that Section 84, is based upon the fundamental principles of:

(a) Actus non facit reum nisi mens sit rea which means that nothing is wrong unless done with a guilty intention

(b) Furiosi nulla voluntas est which means that a person with mental illness has no free will and therefore he/she can do no wrong. This way Section 84 discharges a person with mental illness from his liabilities because of absence of mens rea or an intent.



Under Section 84 IPC legal test of mental illness has been laid down but nowhere in the statute there is a precise definition of terms such as “unsoundness of mind” or “insanity” been given, therefore they carry a different meaning in different contexts and describes varying degrees of mental disorders. To simply differentiate the two, a person suffering from a mental illness is called “medical insanity,” however case of “legal insanity” person suffering from mental illness also have losses his/her reasoning power at the time of the commission of the crime. Legal insanity refers specifically to the “mental state” of a person at the time of committing the crime and is therefore purely a legal concept and have no psychiatric links.



Under the law, every man is presumed to be sane and is assumed to possess a sufficient degree of reason to be responsible for his acts unless the contrary is proved. For proving insanity defence, the burden is always on the accused who has to prove beyond a reasonable doubt that at the time of the commission of offence he/she was “legally” insane.

Supreme Court in Anandrao Bhosale v. State of Maharashtra[vi][ , held that the time when the unsoundness has to be proven is the time when the crime is actually committed and the burden of proving this, lies on the party which is claiming the benefit of Section 84.



It refers to that state of mind when the accused is unable to appreciate the effects of his conduct. It would mean that the accused is insane in every possible sense of the word, and such insanity must sweep away his ability to appreciate the physical effects of his acts



What is required, is to establish that although the accused knew the physical effects of his act, he was unable to know that he was doing what was either “wrong” or “contrary to the law.” In any crime, insanity can undoubtedly be pleaded as a defence, yet it is rarely pleaded except in murder cases. Therefore, in a case, this fine distinction may not be very useful for the decision.



Irresistible impulse is a sort of insanity where the person is unable to control his actions even if he has the understanding that the act is wrong.

Under English Law

Irresistible impulse as a defence was developed in the famous case of Lorena Bobbit (1993)[vii], the defendant took a knife from her kitchen and wounded her husband by cutting off his penis while he was sleeping. Her lawyers contended that she had been suffering from domestic violence, which was perpetrated by her husband during her marriage, and his husband even raped her before she committed this act. Though she was well aware of the consequences, she was not able to control her actions and demanded that she was subject to an irresistible impulse. It was held that she’s not guilty as she was suffering from temporary insanity.

Under Indian Law

Irresistible impulse is not incorporated under insanity because it does not fall within the ambit of Section 84 of the Indian Penal Code.

In the case of, Kannakunnummal Ammed Koya v. State of Kerala (1967)[viii], it was held that to claim an exemption under section 84, the insanity has to be proved, at the time of the commission of an act, mere losing of self-control due to excitement or irresistible impulse provides no defence under Indian law even if this is proved in a court of law.

In another case, Ganesh v. Shrawan (1969)[ix], it was observed that the mere fact that the murder is committed by the accused on an irresistible impulse, and there is no identifiable motive for the commission of the act, can form no grounds for accepting the defence of insanity.



Shrikant Anandrao Bhosale v. State of Maharashtra[x]

In this case, the accused was a police constable. The wife was hit on the head with a grinding stone by the accused, and she was immediately taken to the hospital but was found already dead. After investigation, the appellant was charged for the offence of murder. Insanity was pleaded as a defence. The appellant had a family history where his father also suffered from mental illness. The reason for such an ailment was not known. The appellant was undergoing treatment for this mental disease. It was observed that the motive for the murder was quite weak. After killing his wife, the accused did not attempt to hide or run away.

Based on the above-stated facts, it was held that the accused was suffering from paranoid schizophrenia, and he was incapable of comprehending the nature of the act committed by him. Therefore he was not guilty of murder and was given the benefit of section 84, IPC.



In the present scenario, there are very high chances that the defence of insanity can be very well abused as it is a very strong weapon to escape the charges of an offence. It is impossible to prove that the person was incapable of understanding the nature of the act. Defence lawyers can use it to free the culprits of intentional unlawful acts. The cases of insanity defence or other party holding are subject to critical offense. Though it has some positive aspects like:

-An insane person cannot be given the death penalty, although he confesses his crime, he is incapable to understand the gravity of what he has done. Instead, any lenient punishment could be charged to the accused.

- In some instances, where the mental condition of the accused has been proved to the court, he is neither charged with any penalties nor any acquittal. It all depends upon the mental status he is possessed with.

Though Medically examined insanity could easily be proven, legally it’s a cumbersome task because the party has to collect and submit concrete evidence to prove the insanity crimes. It is extremely difficult to fulfil the essentials phase of Section 84 IPC to show legal insanity. It is for this reason that in many legitimate cases of insanity the accused is charged and punished. In this process, a significant amount of money would be charged. And among all these only the least number of cases goes to success in taking the defense of insanity.

Here the courts play an important role as they have to make sure that a sane person doesn’t absolve himself by wrongfully using the defence in his favour. Thus we must examine such case through fast availability of team such as experts in the field of medical science and specialized with lawyer. In the end, it all depends on how the judge understands the matter and gives his judgment.





[i], Last visited on 10/03/2021

[ii] R v. McNaughton, (1843) 8 Eng. Rep. 718, 722.

[iii], Last visited on 08/03/2021

[iv], Last visited on 11/03/2021

[v] R. v. Chaulk [1990] 3 S.C.R.

[vi] Anandrao Bhosale v. State of Maharashtra, (2002) 7 SCC 748.

[vii] Lorena Bobbitt Biography, Editors, The website,, Last visited on 10/03/2021

[viii] Kannakunnummal Ammed Koya vs State Of Kerala 1967 CriLJ 494.

[ix] Ganesh Shrawan Chaudhari vs State (1969) 71 BOMLR 643.

[x] Shrikant Anandrao Bhosale v. State of Maharashtra (2002) 7 SCC 748.

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