Blog Criminal Law

Insanity as a defense under Indian Penal Code

By: Soumya Verma

Chapter IV of Indian Penal Code

Insanity is one of the defenses available in the Indian Penal Code mentioned under General Exceptions Chapter IV. General exceptions are those exceptions which are mentioned separately under the Code which a person can take to defend his case. These exceptions acts as a shield to protect the defendant under certain circumstances given from S.76-S.106. An offence when fall under these circumstances becomes no offence. The word offence means anything punishable by Indian Penal Code or under any special or local law. A separate chapter has been dedicated to sum up all the exceptions that makes the defendant non guilty in a case, so that repetition is avoided in every section. All the sections of Indian Penal Code have to be read along with these general exceptions mentioned under Chapter IV.

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Therefore these exceptions form a part of every offence, but the burden of proof is on the defendant who claims that his case falls under any of these exceptions in the court of law. We can categorically divide the exceptions under seven heads:

  1. Judicial Acts (S.77, S.78)
  2. Mistake of fact (S.76, S.79)
  3. Accident (S.80)
  4. Absence of Criminal Intent (S.81-86, S.92-94)
  5. Consent (S.87, S.90)
  6. Trifling Acts (S.95)
  7. Private Defense (S.96-106)

Till the time accused does not comes up with any of these defenses that run from S.76-S.106, the court shall presume non existence of such circumstances. When the evidence produced by any of the parties, whether prosecution or defense suggests that facts of the case falls under any of these exceptions, then the presumption of not considering the case falling under any of the general exceptions will be removed and the Court shall consider and decide on the facts and circumstances of the case and evidences products that the general exceptions will apply or not. Investigating officer of a case has to investigate a case keeping in mind all the general exceptions and decide whether an offence has actually been committed or it amounts to a no offence. The burden of proving a case has to be beyond reasonable doubt.

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Introduction to Insanity as a Defense

An act or omission in order to be a crime must satisfy two conditions of being a guilty act done with a guilty mind. This is what we mean by the term “Actus Non Facit Reum Nisi Mens Sit Rea” which is, an act does not make a person liable till the time it is done with a guilty mind. Both gulity act and intention to do that guilty act has to be there. Insanity comes within the general exceptions because it is a mental state which makes a person unfit to be in his cognitive faculties or to understand the probable consequences and nature of the act which he/she is doing. To be benefitted by this exception on has to insure that insanity should be of such an extent that it makes the accused completely incapable of knowing the nature of the act. If a person acts insane sometimes and the other time he understands the nature of what he is doing, then in  that case the Court will decide on the facts and circumstances of the case whether he was capable of knowing the consequences and nature of the acts when he committed it or not. Or in words we can say whether he was insane or not at the time of commission of the offence.

(S.84) ” 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 wrongor contrary to law.”

McNaughten Rule

Defense of insanity was developed in England in a case of R v. Daniel Mc Naughten decided y the House of Lords. In this case Mc Naughten killed the secretary of the Prime Minister of England believing him to be the Prime Minister as he consider the Prime Minister responsible or all his problems. So while he went to kill the Prime Minister, his secretary was killed by mistake. When McNaughten was being tried by the court he showed records of his mental condition before the court and pleaded insanity to be the cause of his action. His plea was accepted and he was not found guilty. This issue was discussed in the House of the Lords and a set of rules was laid down famously known as the Mc Naughten Rules to decide the culpability of an insane person.

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From the rules laid down we can conclude that:  Law presumes every person to be reasonable and sane, to know the law of the land and the consequential result of his act. In case of insanity, human beings deviate from this ordinary presumption and therefore the burden to prove his extraordinary mental condition of insanity is on him. Loss of reason has to there at the time of commission of the offence and such loss should be of such an extent that made the accused fully unaware of the nature and quality of the act in question.

Following are main points of Mc Naughten Rules:

  • Every man is to be presumed to be sane and to possess a sufficient degree of reason to be responsible for his crimes, until the contrary be proved.
  • An insane person is punishable “if he knows” at the time of crime. To establish the defense of insanity, the accused, by defect of reason or disease
  • Of mind, is not in a position to know the nature and consequence, the insane person must be considered in the same situation as to responsibility
  • As if the facts with respect to which the delusion exists were real
  • It was the jury’s role to decide whether the defendant was insane.

Types of Insanity

There are two kinds of insanity Legal and Medical. Legal insanity is the only focus of the court of law and attracts the defense of Section 84 while medical insanity is not to be taken in account by the court. Legal insanity means a state when a person does not understand the nature of the act his is doing. While medical insanity could be of many kinds like an odd behaviour because of not proper functioning of the brain, or a weak intellect etc. will be treated by a medical practitioner as insanity but the court will not consider these as a valid defense under S.84 till the time it satisfies the criteria of legal insanity.

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We do not use the word ‘insanity’ under the Indian Penal Code, but unsoundness of mind which is equivalent to insanity. During investigation, the investigating officer has to subject the accused to medical examination in cases where a previous history of unsoundness of mind of accused is there, so that his current mental position could be fairly judged. This will help the prosecution to strengthen his case. In cases where there is a medical history of insanity, there will be no exemption given to the defendant  from the burden of proof because he needs to specifically prove his claim that the act is question was committed under insanity, and just the fact that there is medical history of his insanity will not serve his claim.

Time of Commission of Offence Matters

Time of commission of offence becomes the most crucial point, as it is during this time that the accused person’s mental condition is to be judged. Not knowing the nature of the act or in cases where he knows the nature then not knowing whether it is wrong or contrary to law will be looked upon to apply S.84. behaviour of the accused immediately before and after the commission of the offence becomes important. In case the accused committed the murder over a trifling matter is not a ground to claim insanity.

In cases where a person becomes insane and sane at certain intervals, then the time of commission of the said offence becomes all the more important because he can commit the offences during the time he was sane and had full knowledge of his act.

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Unsoundness of Mind

Unsoundness of mind can be from the time of birth or arising out from a disease later. In case where a person killed his sleeping  friend by cutting off his head thinking that it would be fun to see when he will wake up and find his head back, we can say that such act was done under unsoundness of mind. But in case where a man sacrificed his son to the deity believing that it will bring good luck to his family, cannot be said to be done under unsoundness of mind because he had full knowledge of what he was doing and its nature because he was expecting good fortune in return of such act. Which means he was fully aware about the nature and consequences of the act. In case muder is done in a sudden impluse and no pre determined motive and intention to kill, will not treated as unsoundness of mind. Just because it was done in a sudden span of time and not by a proper motive and plan does not matter, it will not be the same as a fit of insanity.

Case Laws

Hari Kumar Gond v. State od Madhya Pradesh[1], In this case Supreme Court held that there is no exact definiton of unsoundness of mind given in IPC. We generally treat it to be equivalent to insanity, but even insanity is not defind in law. It could be said to widely cover various degrees of mental disorders. So every mentally ill person cannot be said be be legally insane. A distinction is necessary between mental insanity and legal insanity. Court is concerned only with mental insanity and not legal insanity.

In case of Ratan Lal v. State of Madhya Pradesh[2], Court established that the crucial point of time at which the unsound mind should be proved is the time when the offence was committed and whether the accused was in such a state of mind as to be entitled to benefit from Section 84 can only be decided from the circumstances that preceded, attendant and subsequent to the event that may be relevant in determining the mental condition of the accused ast the time of the commission of the offence but not those remote in time.


According to my view, the concept of insanity we follow in our country suits our needs. There are different concepts that we do not apply in India and it might be included in our laws as the time suggest. We should trust our Parliament and Law Commission to come up with what is better for us at the right point of time. Presently it would be better if we have a concrete defition of the term ‘insanity’ or ‘unsoundness of mind’ as it would highlight the diffrence of understanding that court and medical experts have over the same word. It would also reduce the misuse of this exception.

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[1] (2008) 16 SCC 109

[2] JT 2002 (7) SC 627