Author : Garima Sethi


Crime is constituted when there is a ‘Mens Rea’, ‘Actus Rea and ‘Injury’, these three elements are essential to prove that a crime is committed. Although the ‘Injury’ is not mandatory to prove that an injury is caused. Even if there is an attempt to commit a crime and act was done with an intension to do cause Committing a murder and an attempt to commit murder is also punishable under the act of Indian Penal Code. The elements of crime are discussed below:

  • Mens Rea: Mens Reas is a Latin word which means a guilty mind it is an important element of crime which tells about person’s intention to commit a crime of knowledge that one action or lack of action could cause of crime to be committed. It is the most important element as it sells about how the crime is committed or what was the intention of the accused.
  • Actus rea- it is considered as an object element of a crime like for example z has a guilty mind of committing a crime of murder of now any act done in furtherance of committing this crime will be known as Actus Reus i.e.  Guilty act. No one can take a defense by saying that they were unaware of the fact that if they do or omit to do and act will result in commission of a crime.  Although any act done its intensity and knowledge will be decided by judiciary.


There is a well-established principle under law ` Actus Non Facit Reum Nisi Mens Sit Rea,’ which means, an act to be illegal, the person should do it with a guilty mind, in this module we must learn that whether the accused {mentally ill} is able to understand the nature of the offence or not. The Indian Penal Code 1860, provides immunity to people who are suffering from any mental illness. Under section 85 of Indian Penal Code.  The section talks about act of any person who is unable or incapable of judging the nature of the act whether it is right or wrong or is contrary to law. This section includes both aspects of a person who is under the influence of intoxication or is mentally incapable of understanding the nature of act he/she is committing. The defense of insanity is primarily used in a criminal prosecution, also it is based on an assumption that the offender is incapable and is unaware of the nature of the crime because of his incapability he is not legally accountable for the crime.  The section reads as –

Act of a person incapable of judgment by reason of intoxica­tion caused against his will.—Nothing is an offence which is done by a person who, at the time of doing it, is, by reason of intoxication, incapable of knowing the nature of the act, or that he is doing what is either wrong, or contrary to law; provided that the thing which intoxicated him was administered to him without his knowledge or against his will.

Essentials to take Defense-

  • The accused was either under the influence of intoxication or was suffering from unsoundness of mind – the accused at the time of committing the crime was experiencing unsoundness of mind or was under influence of some intoxication is very necessary to attract the provisions of this section.
  • Accused was incapable of understanding the nature of the act he has committed- the accused who has committed the offence does not have the capability to understand the nature of the offence committed, the accused cannot take a defense that there was a supernatural intuition. 


Although there were many tests all over the world to test the nature of mentally ill person when committed a crime but the Mc Naughten`s rule or test was done to determine ` wrong and right`. Mc Naughten`s case had indirectly made clear that a person who is unable to understand what is wrong and what is right, and whether the act will lead to some criminal consequences he`ll be not legally liable for commission off that act because he is clearly does not have a potential mind that can understand the nature of any act. In Mc Naughten`s case judgment there were 15 judges in a panel who were supposed to understand the nature of the act and 14 of them were in the view that mental illness may lead to a situation where the person might not be capable of understanding the nature of the act.  We cannot say that some mental illness may always be dealt as, the accused is suffering from mental illness will always be given exemption or protection by law, this rule of protection does not apply everywhere. There are cases were an accused is guilty of an offense and is suffering from mental illness but isn`t given protection under law[1]. This is because of some acts or words spoken which clearly prove that at the time of commencement of the act the accused was in senses and was able to judge the nature of his act. 


Although the burden of proof of commission of the act is always on the prosecution to prove that the offence was

  • Committed with guilty mind
  • With an intension to cause hurt
  • Had a reason to believe that the act was criminal in nature
  • Was done out of revenge or anger

The accused has to prove-

  • He was mentally ill at the time of commission of the act
  • He was unable to judge the nature and consequences of his act
  • He should bring out orally, evidentiary documents to support his mental illness and to take defense under section 84.


In this module we have learnt about the exemption under the Indian Penal Code, Section 84.  The nature of defense ingredients of the protection, Mc Naughton’s rule and burden of proof are discussed in detail.


S.K. Nair Vs. State of Punjab