insanity defence


Insanity Defense or Plea is a tool that saves an insane person in a criminal trial after a commission of a crime. It is a legal concept that is based on the assumption that if an insane person commits a crime and on the reasonable ground is believed to be insane and lacks knowledge about the consequences of his/her action, then he/she can plea insanity as a defense in the court. An insane person is a one who suffers from mental illness or disorder due to various psychological factors like anxiety, depression, or suffers from mental illness since its birth. Mental disorder is not only sufficient to prove insanity as proof.

The burden of proving insanity lies on the person who claims him/her to be insane and has to produce proper evidence which claims them insane. The insanity defense is basically a defense wherein criminal admits its crime but use lack of knowledge due to mental illness or mental disorder as a defense in the trials. Many criminals take undue advantage of insanity as a defense and plead false insanity in order to get rescued from being punished during their trials. “Insanity defense in court is generally used as an excuse rather than being the justification of facts and the crime.”[1] It can be also used as a loophole in the judicial system in order to escape from the punishment during the trial.


Insanity defense took a legal position in the last three centuries but it has been into existence for decades. A provision regarding the insanity defense came into the eyes of the English Legal System in 1851.” There were 3 tests that laid the foundation for the landmark Mc Naughten Rule. These 3 tests were The Wild Beast, The Insane Delusion Test, and Test of Capacity to Distinguish between Just and Unjust.” The rule became a legendary precedent for the law which is also applicable in the Indian Legal System and comes under Section 84 of the Indian Penal Code, 1860.  “There were 5 propositions in Mc Naughten’s Rule:

  1. There is a presumption that the accused at the time of committing offense has the proper knowledge and hence would be held responsible for his/her acts.
  2. At the time of the commission of an offense insane person would be liable if they have knowledge of their actions
  3. In order to plea defense of insanity, the accused at the time of commission should not be in a position to know the nature and consequences of their actions.
  4. The illness or disorder of accused should be real
  5. The English Law would be held responsible and decide whether a person is insane or not [2]

Insanity Defense is given in Indian Law under Section 84 of the Indian Penal Code, 1860 under “Act of the person of unsound mind which states that nothing is an offense 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.[3]

Section 84 of the Indian Penal Code is based upon 2 fundamental principles:

  1. Actus nonfacit reum nisi mens sit rea which means an act does not seem to be guilty if it is not done with guilty intention or motive
  2. Furiosi nulla voluntas est Furiosi nulla voluntas est which means a person with mental illness has no free will.[4]

Section 84 of the Indian Penal Code, 1860 has the following essentials which can be divided into 2 broad categories:

  1. MAJOR CRITERIA: It consists of the medical and mental requirement of the ill person which means a person should be suffering from some mental illness or disorder at the time of the commission of the offense.
  2. MINOR CRITERIA:  It consists of loss of knowledge that a person at the time of the commission of an offense is incapable of knowing nature, wrongful acts, and that his/her actions are contrary to the law.


In a layman’s view, there are broadly 2 categories of insanity which are the following:

  1. TEMPORARY INSANITY: It is the type of insanity where the insane person suffers from specific mental disorders or illness for a time period due to various reasons such as anxiety, depression, stress, or any other psychological factors for some period or point of time. The person suffering from temporary insanity can have 2 possible reasons as a plea; either he/she are not guilty because of the insanity or guilty but cannot be tried because of the insanity.
  2. PERMANENT INSANITY: It is the type of insanity where the insane person suffers from continuous mental disorder or illness either from the time of the birth or any past record, if. In this type of insanity, the insane person is incapable of knowing consequences ever as recovering from permanent insanity is rarest.


Like a double-edged sword cuts in both ways, insanity in this judicial system also has 2 implications.

  • Insanity as A Positive Aspect

  1. It establishes guilt: When an insane person is tried in court, he/she pleads themselves guilty and hence uses insanity as a defense. The ill person is not tried harshly for the commission of the offense but they are kept off the roads in order to avoid future commission as they cannot distinguish between what is right and not right.
  2. It does not allow harsh punishments: An insane person who is tried in the court for the offense is not punished with the death penalty or any harsh or rigorous imprisonment. If the insane person needs to be punished, he/she is prescribed to very lenient punishment. This is because the person fails to understand the gravity of their actions or is lacking knowledge about the consequences of the action due to their mental illness or disorder.
  • Insanity as A Negative Aspect

  1. It is a loophole for criminals: An accused whether sane or insane misuse Section 84 of the Indian Penal Code, 1860 and try to escape from the punishment. They use insanity as a false ground on the pretext of defense. Criminals use insanity as a loophole in order to escape the punishment and to not get convicted during the trials. The plea can be abused by sane persons. Though guaranteed as a privileged defense for the insane by the judicial system many sane people take undue advantage and abuse this privileged defense.
  2. The burden of proof lies on the insane person: An insane person in the eyes of law has to prove his insanity by producing evidence that clearly establishes them insane. This process consumes a lot of time and proves to be very costly for the accused as along with the cost of court proceedings, he/she has to bear the medical cost of the examination. The burden of proof to prove them insane or suffering from mental illness or disorder lies in the insane person itself. In order to establish the medical records of the insane person, it would take time and hence it would delay the justice and in case if the person is sane and abuse the defense of insanity he would be set free for the time being which is very risky cause one is not aware of his/her intentions or motive. Such a person is not only concerned with mental insanity but also legal insanity.


The insanity defense is a privileged defense guaranteed by the Indian Legal System for the insane person. Insane person by using insanity as a defense given under Section 84 of the Indian Penal Code, 1860 would be entitled to very lenient punishment or possible chances of acquittal. Here an insane person commits a crime and can be acquitted even after pleading guilty or subjected to very lenient punishment on the ground of lack of knowledge or incapable of knowing what is right and not right. An insane person has to prove their insanity in the eyes of law by producing proper just and fair evidence which declares them insane or having a lack of knowledge about the consequences of their actions.

A sane person who has absolute knowledge of the consequences of their actions and who can even differentiate between what is just and unjust abuse insanity as a defense in order to get acquitted by the crime they commit. They misuse the power of insanity defense so that in case they have committed heinous or cognizable crimes like murder, abduction, or rape or any other according to the prescribed act they will be subjected to lenient punishment or no jail term at all.

A sane person commits an offense and pleads them insane in eyes of law as they think that they can easily away after the commission of an offense. At times a sane person can even manage to prove that they are insane by manipulating the reports which prove them insane. Corruption, poverty being the root evil of the nation, and mishandled by powerful man can cause abuse in the judicial system of the nation. At times a sane person can even manipulate the evidence produced in the court by giving false evidence with the help of political power or financial aid in this developing nation.

Insanity is used as a defense and is a loophole for criminals. To prove insanity, it would consume a lot of time and hence this would delay justice and be an abuse to the judicial system of the nation. Criminals are basically exempt from any sort of punishment by using insanity as a defense. Criminals abusing the insanity defense have the proper knowledge and motive to cause injury harm, grievous hurt, or even murder them and hence perform the act having the intention to do so.

It helps the sane person to use the insanity defense as the last medium and plead themselves guilty in the court in order to get an easy acquittal or possibly no punishments or penalties by the judicial system. It is very difficult to predict whether the person is sane or not and even during those periods criminals can use other mediums and try to use other coercive power in order to get free from the court proceedings.

When the evidence is proved in the court it is under the discretion of the judge whether to pass the judgment in favor or against that person and whether to punish him/her or not. The sane person or the criminals can even threaten the judges through political power or suppress them or can even bribe them. Even some criminals are so dangerous that if some people want to serve the legal system with proper and clean motive these people also have a risk to lose their lives or the risk of losing any of the family members or can even have a loss of their goodwill and reputation as the evil minds can use evil mode with very clever motive and not even get caught.

Criminals use the insanity defense and think that the legal system is sleeping and they can easily fool them and roam freely without any punishment for the crime. Even after having laws and amendments criminals use insanity as the biggest loophole in order to plead their defense in the court.


Under Section 84 of Indian Penal Code, 1860 their test prescribed in order to prescribe the mental illness of the person but there is no absolute test laying down provision for the term’s insanity and unsoundness of mind.  A person who suffers from mental illness is not always exempted from the punishment as there is a difference between legal insanity and medical insanity.

A person who suffers from mental illness is known as Medical Insanity and the person who suffers from mental illness and incapable of knowing what right and wrong are at the time of the commission of a crime is known as Legal Insanity. In case of legal insanity psychiatric does not deal with them these people are dealt at the courts. In order to be legally insane, the person at the time of committing the crime incapable of knowing the nature of the act, the act being conducted is wrong and it is contrary to the law.

“In the case of [email protected] SINGH V/S STATE OF RAJASTHAN ON 4TH JUNE, 2007 the apex court held that there is abnormal behavior by the appellant which requires medical treatment and needs to be treated by a good mental hospital and does not attract Section 84 of Indian Penal Code, 1860 and is a case of Medical Insanity”[5].

“In the case of SURENDRA MISHRA V/S STATE OF JHARKHAND ON 6TH JANUARY,2011 the apex court held that the appellant was suffering from Schizophrenia and not of any unsoundness of mind at the time of the commission of a crime.  There the person is not exempted from criminal liability as he was suffering from Legal Insanity and attracts the provisions of Section 84 of Indian Penal Code, 1860”[6].


Hence insanity defense can be used as even a weapon or as a protecting guard by the criminals in this legal system. There is a need to distinguish between medical insanity and legal insanity in order to avoid future conflicts and confusion. Criminal laws are basically based on a concept that criminals commit a crime within their own intention and not under any influence, threat, or coercion and hence would be held guilty and be punished for the same. “Hence, two elements have to be proved without leaving any grounds for doubt which are:

  1. ACTUS REUS: It means the person who commits the crime
  2. MENS REA: It means the person who commits the crime does with his own intention will and knowledge”[7].

Here the insane person committing the crime does not constitute Mens Rea and hence lacks the proper knowledge and is incapable of distinguishing between what is right and wrong. There should be more provisions in Section 84 of Indian Penal Code, 1860 which lays down provisions for committing heinous crimes like murder, rape or any other cognizable offense so that even when any sane criminal tries to take undue advantage of the insanity defense they also fail and think for zillion times before committing such a heinous crime. By doing this even there would be fewer loopholes and fewer crime rates and criminals would also stop using the insanity defense and stop causing a hazard and fooling the judicial system.

There is a need to expand the scope and ambit of Section 84 of IPC, 1860 in order to avoid future occurrence of such crimes and criminals using the same as a loophole in order to be set free and avoiding any punishment for the same under the trials.


Snigdha Singhi Snigdha Singhi | Amity Law School, Noida


[1] (July 10, 2020 2:25 PM),

[2] (July 11, 2020, 10:12 AM),,the%20accountability%20of%20a%20crime.&text=It%20is%20to%20be%20noted,not%20sufficient%20to%20prove%20insanity.%20Ipc%20def


[4] (July 13,2020, 11:11 PM),

[5] MANU/SC/7754/2007

[6] (2011)  3 SCC (Cri.) 232

[7] (July 15, 2020, 4:56 PM),


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