Insanity As A Defence To Crime Under Criminal Law


In India insanity as a defence to crime is an unsolved problem of criminal jurisprudence. However, It presents some fascinating problems that deserve careful analysis. We know that there is a well-established principle,“ Actus Non-Facit Reum Nisi Mens Sit Rea” which literally means, an act does not make an offender liable without guilty mind. The intention or the guilty mind of the offender is an integral part while committing a crime. The defence of insanity is a law that protects a person who is incapable of understanding the nature of the act done by him. This article focuses on the defence of insanity with important decisions of court.

Meaning of insanity

Insanity means a state of mind in which one or more of the functions of feeling, knowing, emotion and willing are performed in an abnormal manner or is not performed at all by reason of some disease of the brain of the nervous system.

Insanity includes lunacy, mental derangement, mental disorder, madness and so on.

Insanity defence

Insanity defence refers to a defence where a criminal admits the action but there is an absence of understanding based on mental illness. That is why it is more of an excuse rather than a justification of what he/she has done.

Historical background of insanity defence

Laws related to insanity as a defence of crime has been a part of man-made laws since ancient Greece and Rome. However, it took a legal position only for the last three centuries. There were various tests used to declare a person legally insane such as:

  1. Wild Beast test
  2. The Insane Delusion test
  3. Test of capacity to distinguish between right and wrong.

These three tests laid the foundation for the landmark M’naghten rule or principles of insanity. The following principles were cited:

  1. If the person knows what was doing then he is punishable.
  2. There is an assumption that every man is sane and known what he is doing is responsible for the same.
  3. To establish a defence, it must be ascertained at the time of the act, the accused was in such a state of mind as was unable to know the nature of the act.
  4. A medical witness who has not seen the accused before trial should not be asked to give his opinion as to the state of the accused’s mind.

Insanity defence in India

In India M’naughten’s principles of insanity have been incorporated under Section 84 of the Indian Penal Code, 1860. However, the term insanity is not used under the provision. The Indian Penal Code uses the sentence “mental soundness”.

Section 84 states 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 law.

Ingredients of Section 84 are:

  1. The act must be done by a person of unsound mind.
  2. Such a person must be incapable of knowing the nature of the act, that act was contrary to law and the act was wrong.
  3. Such incapacity must be because of unsoundness of mind.
  4. The incapacity of knowing the nature of act must exist at the time of doing the act.

The burden of proving insanity

The burden of proving insanity would lie with the accused, as provided in Section 105  of the Indian Evidence Act because Section 84 IPC provides immunity from criminal prosecution to persons of unsound mind.

The accused has to prove by placing evidence such as oral and written documentary that would show that he was incapable of knowing the nature of the act.

Important decisions on the insanity defence

Bapu @ Gajraj Singh v. State of Rajasthan (2006)

The Supreme Court held that mere abnormality or partial delusion, irresistible impulse or compulsive behaviour of a psychopath affords no protection of law under Section 84 IPC.

Surendra Mishra v. State of Jharkhand (2011)

In this case, the Supreme Court held that Section 84 of IPC is only for legal insanity and not medical insanity and therefore a person suffering from mental illness is not exempted from criminal liability. It is the circumstances based on the evidences that are essential to prove that the person was unable to understand the nature of his act.

Ratanlal v. State of Madhya Pradesh ( 1970)

Here the court established that it is the behaviour precedent, attendant and subsequent to the event that may be relevant in determining the mental condition of the accused at the time of the commission of the offence but not those remote in time.

Shrikant Anandrao Bhosale v. State of Maharashtra (2002)

In this case, the accused police constable hit his wife with a grinding stone and she was immediately taken to the hospital but was found already dead. After the investigation, the appellant was charged for murder. He pleaded insanity as defence. It was observed that his father also suffered from mental illness and he was undergoing treatment for mental disease. Also observed that the motive for the murder was quite weak and therefore he was not guilty of murder and will be given the benefit of section 84 IPC.

Paras Ram v. State of Punjab (1981)

Where a father and his relatives sacrificed a four-year-old boy to propitiate the deity, the supreme court observed that this does not itself constitute insanity. Such human actions must be punished severely to deter others from such practices.

In Re Pappathi Ammal (1959)

It was observed that somnambulism is the unconscious state known as walking in sleep and if proved will constitute unsoundness of mind and the accused will get the benefit of section 84 IPC.

Seralli Wali Mohammad v. State of Maharashtra (1972)

The offender was charged under Section 302 0f IPC for causing death of his wife and daughter with a chopper. The Supreme court rejected the plea of insanity because the mere fact that there was no motive proved, or that he did not attempt to run, was not sufficient enough to prove that he did not have the mens rea for committing the act.

Jai Lal v. Delhi Administration (1969)

Here the appellant killed a small girl with a knife and even stabbed two other people. He was convicted under Section 302 IPC. It was pleaded by the accused that he was suffering from insanity. It was observed that the accused, after being arrested, gave normal and intelligent statements to the investigating officers. Nothing abnormal was noticed in his behaviour. Considering all this findings, the supreme court held that the appellant was not insane at the time of the commission of the act and he was held guilty for murder under Section 302 IPC.

Basdev v. State of Pepsu (1956)

It was observed that where insanity is caused by excessive drinking, even involuntary or by smoking ganja or other drugs, such insanity will also amount to unsoundness of mind if it makes a person incapable of understanding what he is doing or that what he is doing something wrong or illegal.

Positive features of the insanity defence

  1. It is a good solution where the accused is really insane. But now such legitimate cases are rare.
  2. This prevents capital punishments because an insane person who confessed crime is incapable of understanding the guilt of offence. Therefore giving capital punishments is justifiable.
  3. In India, this provides relief to insane persons. If availed the accused by this can be formally discharged.
  4. It is more like a life-giver.

Negative features of the insanity defence

  1. Misuse of this defence, it has been abolished in many countries like Germany, Argentina, Thailand etc.
  2. It is a very big challenge to prove the insanity that it is extremely difficult to fulfil the essentials of Section 84.
  3. This defence can be misused to escape from punishment. The difficulty in proving insanity at the time of commission of crime leads to punishment of really insane persons who sought for the protection of law. By this in one way or other way law losses its essential purpose.


This article focused on the importance of the insanity defence in India and also on the leading Supreme court decisions. From that, we can conclude that the insanity defence has become a loophole for crimes and as the most popular defence to escape from any crime, even though it is a big challenge to prove the insanity. For these reasons it could safely be concluded that insanity defence law lost its original zeal in the modern judicial system. It is in the hands of judges to analyse the circumstances and to decide properly as to fulfilling the purpose of law. The forensic Psychiatric Informal training and Clinical Services Providing Centers are few in number across the country. To provide a fair and speedy trial, forensic psychiatry needs to be given utmost importance.


  1. LAW OF CRIMES [Indian Penal Code 1860], Dr.S.R.Myneni, 3rd Edition,Asia Law House Hyderabad
  3. Indian journal of Psychological Medicine,2015,vol 37,Issue 4

This article is authored by Adhithya KP, BBA LLB student at Nehru Academy of Law.

Also Read – What is the Right of Private Defence of a Person?

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