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In our judicial system, the accused has the right to put forward side and also allow them to take defense under certain provisions of law. Defense of Insanity is one of the defenses which are used by the criminals in the prosecution. It means that the defendant was mentally ill at the time of the crime and was not able to understand the nature of the crime. A mentally ill person cannot be punished because he/she does have any free will to commit the crime. Section 84 of the Indian Penal Code states “Nothing is an offense which is done by a person who, at the time of doing it, because 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 law”.


Under the Indian Penal Code, Men’s rea is the necessary element to constitute a crime. If there is an absence of men’s rea, then such falls will fall under General Exceptions given in sections 76-106 of the Indian Penal Code. In the British case, R v. McNaughton[1] which is the basis of section 84 of the Indian Penal Code. In this case, McNaughton killed Edward Drummond mistaking him for another person, he took the plea of insanity that he was not sane at that time and the Court acquitted him. It devised McNaughton’s test of knowing what is right or what is wrong. The burden of proof lies upon the accused that at the time of the crime, he/she was insane. In the case of Anandrao Bhosale v. the State of Maharashtra[2], it was held that the burden of proving unsoundness, at the time the actual crime was committed, is on the party who is claiming the benefit under section 84 of the Indian Penal Code.


  • Temporary insanity: – The insanity which is only for a particular time or periodically. Such as depression and anxiety. The possible two outcomes are ‘not guilty because he/she is insane and another one is ‘guilty but cannot be tried because he/she is insane.
  • Permanent insanity: – A condition in which the person is persistently insane due to medical illness. This can be proven by the past events and medical reports of the accused which show that the person is permanently insane and cannot understand what is right or wrong.


Under Section 84 of the Indian Penal Code 1860, the defense of insanity was provided. This section provides no culpability to persons who are suffering from mental illness. This section can be divided into two categories:-

  • Major criteria: It consists of the medical requirement of that person which shows that the person is suffering from mental illness at the time of the offense committed.
  • Minor criteria: It means that the person was not able to think rationally at the time of the offense.


The insanity defense is a lifesaver for mentally challenged people as they are incapable of understanding what is right or wrong and the nature of the crime that they are committing. Although he must accept the crime. That person cannot be given a death sentence because he was not able to understand the seriousness of the act. In some cases, the accused was neither charged with any kind of penalty nor acquittal.


 This defense has been frequently misused by criminals to escape from acquittal. It becomes very difficult to conclude that the criminal is of sound or unsound mind at the time of the crime. The accused bears the burden to prove his mental illness. To prove the insanity, a specialist needs to be hired which will ultimately increase the cost of the trial, and only in a few cases, does the criminal successfully take the advantage of the defense of insanity.


Although Section 84 of the Indian Penal Code lies down the legal test of mental illness this section does not define the terms“unsoundness of mind” or “insanity” and their interpretations can vary from person to person. Only mental illness does not exempt the person from criminal liability because there is a difference between legal insanity and medical insanity and the courts only recognize legal insanity. When a person suffers from legal insanity, he/she loses his/her power to think rationally. In the case Surendra Mishra v. the State of Jharkhand[4], it was held that section 84 of the Indian Penal Code is only for legal insanity and not for medical insanity and the person suffering from medical insanity cannot be exempted from culpability.


This defense is generally misused by criminals who are of sane mind and have knowledge of their actions and consequences but they show that they lack rational thinking. The criminals who are of sane mind think that they will get escaped from punishment and other liability after doing heinous crimes and it is very unfortunate to say that in some cases they get escaped too by threatening the doctors and misrepresenting the reports. Furthermore, criminals can easily manipulate the witnesses and the evidence. This principle seems an opportunity for the criminals instead of a defense. Since there is no restriction in this defense.


It has been noticed that the defense of insanity is also a boon to the persons who are insane and also a curse to society as it is misused by criminals. Criminals think that they can do anything they want to do as they can escape using this defense which is a threat to society. Also, it seems impossible to prove that a person is sane or insane. Medical tests can help in evaluating whether a person is sane or insane but criminals can easily manipulate the medical reports and can threaten medical practitioners. Even after several amendments and strict laws in India due to these loopholes, criminals can easily escape without getting any punishment.

Author(s) Name: Garima Kamboj (University Institute of Legal Studies, Panjab University,Chandigarh)


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

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

[3] Vaidehi Gupta, Insanity defense: A loophole for criminals, <>  on 26th August 2022

[4] Surendra Mishra v. the State of Jharkhand (2011) 3 SCC (Cri.) 232.