Insanity defence: A loophole for criminals

Insanity Defence

In Indian Legal System “Insanity Defence” is a tool in criminal law to save an alleged from the accountability of a crime. It is based on the assumption that at the time of the crime, the person was suffering from mental illness and therefore, was incapable of understanding what he/she was doing. It is to be noted here that this is a legal concept and therefore simply suffering from a mental disorder is not sufficient to prove insanity. The burden of proof to prove insanity is on the alleged and he/she has to supply the court with evidence similar to that of “preponderance of the evidence” as in the civil case. This article focuses on the concept of insanity in law and how it has become a loophole in the modern judicial system.

What is Insanity Defence?

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

In India, Section 84 of the Indian Penal Code describes the defence of insanity. Under the provision of Section 84, the law protects an unsound minded person and provides him/her defence from criminal liability, which is also known as the Law of Insanity. This law is based upon the assumption that whenever an insane person commits a crime in a fit of insanity, he/she does not have a guilty mind to understand what he/she is doing, and that the act is prohibited by law. For these reasons, Insanity law has proven to be of great importance in understanding the mental position of an insane person and in suitable circumstances grant them exemptions from criminal charges.

Origin of Insanity Defence

Laws related to Defence-insanity has been a part of man-made laws since ancient Greece and Rome. A provision related to Insanity Defence was first recorded in a 1581 English legal treatise wherein, if a lunatic in the time of his lunacy kills someone, they cannot be held accountable. With further developments in jurisprudence, the British courts in the 18th Century came up with the “Wild Beast” test by virtue of which a defendant was not to be convicted if he/she had an understanding of an infant or a wild beast.[i]  This test was the first formal enactment which led the basis for Law of Insanity and with this marked the advent of Insanity Defence.

Following the “Wild Beast Test”, various other tests were also deduced to check if a person is legally insane such as the Insane Delusion test[ii] , the Good and Evil test wherein it was to be seen that the person who had committed some crime has the ability to distinguish between good and evil .[iii] These three tests were the early laws relating to Insanity Defence and laid the foundation for the landmark Mc-Naughton Test.

The English Courts in R v. McNaughton[iv], devised the McNaughton’s Test which formed the basis of modern-day Insanity Law and is also the basis of Section 84 of the Indian Penal Code. In this case, a man named McNaughton killed Edward Drummond mistaking him for some other person. His state of mind was not sane and therefore the court ordered for his acquittal. But the jury considering him insane and therefore brought in a verdict of admitting him in a Mental Asylum. After this judgment in 1843, there was a discussion in the House of Lords, where a five-point proposition was made. These five propositions were construed as the McNaughton’s rules. The propositions were as follows:

1.That it is to be presumed that a convict is sane until the contrary is proven.

2.That an insane person would be liable for punishment if he/she knows at the time of the commission of crime what he/she is doing.

3.That to establish a defence on insanity, the accused by way of his/her insanity should not be in a position to know the nature and consequences of his/her act.

4.That the delusions to which the accused is suffering should be real.

5.The jury in English Law is responsible for deciding if someone is insane or not.

These propositions became precedent for the law concerning the defence of insanity. The rules emphasized the observation of “understandability” of an accused in a case where he/she has done something wrong. It is a test of knowing what is right and wrong.

Defence by Insanity in Indian Law

Provision for Insanity Defence is given under Section 84 of IPC under “Act of person of unsound mind” which states that nothing is an offence 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.

 Analysing the aforementioned Section, it is clear that the provision is much influenced by the McNaughton’s Test, and since it is based upon the 5-point propositions it is divided into two broad categories, first being Major criteria which cover cases where the person was suffering from mental illness during the crime and the Second being Minor criteria which cover cases:

1. That the person was incapable of knowing the nature of the act,

2. That the person was incapable of knowing that his/her act was wrong,

3. That the person did not know that what he/she was doing is contrary to law.

Under both these criteria, the insanity is legal insanity and therefore once proven the accused could be acquitted.

It is also to be noted here that Section 84 IPC, is based upon the fundamental principles of,

(a) Actus nonfacit reum nisi mens sit rea which means that nothing is wrong unless done with a guilty intention and

(b) Furiosi nulla voluntas est which means that a person with mental illness has no free will and therefore he/she can do no wrong. This way Section 84 discharges a person with mental illness from his liabilities because of absence of mens rea or an intent.

Medical Insanity v. Legal Insanity

Under Section 84 IPC legal test of mental illness has been laid down but nowhere in the statute there is a precise definition of terms such as “unsoundness of mind” or “insanity” been given, therefore they carry a different meaning in different contexts and describes varying degrees of mental disorders.[v]  A person with mentally illness is not simply exempted from criminal responsibility because there is a distinction between legal insanity and medical insanity and courts are concerned only with legal insanity.[vi]  To simply differentiate the two, a person suffering from a mental illness is called “medical insanity,” however case of “legal insanity” person suffering from mental illness also have losses his/her reasoning power at the time of the commission of the crime. Legal insanity refers specifically to the “mental state” of a person at the time of committing the crime and is therefore purely a legal concept and have no psychiatric links. For insanity to qualify for legal insanity any one the 3 essentials of Section 84 as mentioned earlier must be fulfilled and only then the accused can seek a defence by way of insanity.

In Bapu @ Gajraj Singh vs State of Rajasthan[vii], Hon’ble Supreme Court held that Mere abnormality of mind or partial delusion, irresistible impulse or compulsive behaviour of a psychopath affords no protection under Section 84 IPC.

Hon’ble Supreme Court in Surendra Mishra v. State of Jharkhand[viii] , held that Section 84 IPC is only for legal insanity and not medical insanity and therefore a person suffering from mental illness is not exempted from criminal liability.

Therefore, under Section 84 of the Indian Penal Code, it is not only that the person is suffering from mental illness but it is the circumstances based upon evidences that are essential to prove that the person was also unable to understand the nature of his act and committed a crime.

Burden of Proof

Under the law, every man is presumed to be sane and is assumed to possess a sufficient degree of reason to be responsible for his acts unless the contrary is proved.[ix]  This way Insanity Defence is more like a divergence from the general law and therefore to prove and avail Insanity Defence there are specific provisions prescribed under law. For proving insanity defence, the burden is always on the accused who has to prove beyond a reasonable doubt that at the time of the commission of offence he/she was “legally” insane. The accused has to prove by placing evidences such as oral and written documentary that would how that he was incapable of knowing the nature of the act or that his/her act was contrary to law.[x]  Hon’ble Supreme Court in Anandrao Bhosale v. State of Maharashtra[xi] , Held that the time when the unsoundness has to be proven is the time when the crime is actually committed and the burden of proving this, lies on the party which is claiming the benefit of Section 84. In T.N. Lakshmaiah v. State of Karnataka[xii], the Apex Court has observed that the burden on the accused is only to satisfy the preponderance of probabilities which makes it similar to that of civil cases.

Positive Aspects of Insanity Defence Laws

1. It is a solution in cases where the accused is, in reality, a person with some mental issues and therefore comes to his/her aid, although in present time legitimate cases with such issues are in a minority. 

2. This defence prevents capital punishments because an insane person who has although confessed his/her crime is incapable to understand the gravity of what he has done and therefore giving capital punishment is unjustifiable.

3. In a country like India where an accused of some crime is considered lesser human, this defence provides relief to a mentally challenged person. If availed the accused by this can be formally discharged and acquitted. 

4. For a mentally challenged person, this defence is more like a “life-giver” because his/her state is similar to that of a child who does not know about what he/she is doing and is unacquainted with the consequences. Therefore, imposing burdensome charges on such a person would be against morality.

Negative Aspects of Insanity Defence Laws

1. Considering the present-day misuse of this defence, the Law of Insanity has been abolished in any countries. Countries such as Germany, Argentina, Thailand and many counties in England have already abolished such defences. An analogical example would be wrong to draw out here but considering the misuse of this defence in multitudinous cases wherein, brute Criminals gets acquittal on the ground of insanity simply demeans the very notion the law was built upon.

2. As already been dealt with in the article, proving Insanity and availing this defence is upon the accused and it is a very big challenge to prove the same. Though Medically insanity could easily be proven, legally it’s a cumbersome task because the party has to provide concrete evidence to prove the insanity. It is extremely difficult to fulfil the essentials of Section 84 IPC to show legal insanity. It is for this reason that in many legitimate cases of insanity the accused is charged and punished. 

3. The defence of insanity can be misused to escape from the acquittal or punishment. It is very difficult to examine whether the person was of sound mind or unsound mind at the time when the crime was committed. This way the case depends upon the prudence of the judge and in one way or the other the law losses its essential purpose.


As of now, we can concur that Insanity Defence has become a loophole for the criminals as the most popular defence to escape from any crime. It is next to impossible to prove the mental status of any person at the time when the crime was committed. The redundancy of Indian Judicial System is also to be blamed here because it simply adds fuel to the fire which makes this defence lose its stark, and all that matters are word-games. These cases are more complicated than any other case because here an accused agrees to the commission of a crime but evades the consequences and this raises brows of any right-minded person.

For these fundamental reasons it could safely be concluded that Insanity Defence Law has lost its original zeal and has now become a tool for criminals to evade legal consequences. Now the remedies available to cope up with these lacunas are the formation of more straightforward laws and tests. The initial step towards reforms could be a mechanism to differentiate between Violent criminals and Insane criminals, wherein the former are the real culprits. Reforms here can only be possible when states would make stricter laws to govern such matters and it is high time now for major reforms in these provisions.

Edited by Shikhar Shrivastava

Approved & Published – Sakshi Raje


[i]R. v. Arnold. 1724, 16 St.Tr.695

[ii]Hadfield Case. 1800, 27 St.Tr.128.

[iii]Bowler’s case. 1812, 1 Collinson Lunacy 673.

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

[v]Hari Singh Gond v. State of Madhya Pradesh. (2008) 16 SCC 109.

[vi]Supra note 5.

[vii]Bapu @ Gajraj Singh vs State of Rajasthan. Appeal (crl.) 1313 of 2006. Date of Judgement on 4 June, 2007.

[viii]Surendra Mishra v. State of Jharkhand. (2011) 11 SCC 495.

[ix]State of M.P. v. Ahmadull. AIR 1961 SC 998.

[x]State of Rajasthan v. Shera Ram @ Vishnu Dutta. (2012) 1 SCC 602.

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

[xii]T.N. Lakshmaiah v. State of Karnataka. (2002) 1 SCC 219.