Insanity plea



The subject of criminal liability and mental illness is still an unsolved question of criminal jurisprudence. And Insanity plea is one of the significant laws imposed by the law intellects, presents some fascinating problems that generally deserve careful analysis. In due course of the article, we only have to focus on whether this law has corrected consequences or not in general living. 

Insanity primarily belongs to criminal prosecutions, and it is based on the assumption that at the time of the crime, the defendant was suffering from mental instability or illness and was incapable of determining the right and wrong decisions at the time of committing the crime, hence do not make that person legally bound to the crime. The defense of insanity cannot be understood in terms of foresight of consequences alone; this concept has its importance in law in which board thinking is highly required. 

According to the Black law dictionary, Criminal insanity means a state of mental illness where a person cannot determine between right and wrong, and as a result, will commit unlawful acts. However, this form of justice also has its dire consequences, which are wrongly justified in the court of law to save the accused and make the innocent suffer.

Yes, this concept is readily concentrating to the guilty act by the guilty mind which may be unsound at the time of committing the act, and for which there is a common phrase “Innocent until proven guilty” and for this Under Indian law, the rationale insanity plea is incorporated in Section 84 of Indian penal code, 1860. 


insanity plea


In the legal system, two terms define a court of law’s whole perspective, i.e., mens rea and actus reusWhich meaning guilty mind and guilty act.

The insanity plea derives from the idea that mental distress and instability can interfere with an individual’s ability to form means rea as required by the court of law. Punishing a person on the stage in which that person cannot defend himself due to mental instability and further not responsible for the act is a direct violation of Human rights and Fundamental rights under the constitution of India. Hence, it further concludes that incapacity to commit crimes exempts the individual from severe punishments.

The first known case of insanity, i.e., R vs. Arnold (1724) as a defense to the criminal charges applied to a person, was recorded in 1581. The English intellect stated, “If a madman or a natural fool or a lunatic doing wrongful act in the time of his lunacy, they can’t be held accountable.” And after that, various British laws came in which “wild beast test” is one of the major tests in which defendants were not convicted if they were declared insolvent. Besides all the facts, the “Wild Beast test” is no longer useful; thus, the English intellect codified the insanity into British law with M’Naughten Rule.

The M’Naughten Rule became a legendary rule imposed by law intellects concerning the defense of insanity, and even in India, the same direction is applied as insanity plea law, Section 84 of Indian Penal Code, 1860 and continuously without any changes, this law is applicable for the citizens of India.


Section 84 of IPC states, “Act of a person of unsound mind.” —Nothing is an offense which is done by a person who, at the time of doing it, because 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.

Section 84 of IPC signifies both the primary (mental illness) and minor (loss of reasoning) criteria constitute legal insanity. As the fundamental maxim of criminal jurisprudence states, “Actus nonfacit reum nisi mens sit rea” (an act does not constitute guilt unless done with a guilty mind) and “Furiosi nulla voluntas est” (a person with mental illness has no free will). Hence, Section 84 of IPC maintains no blame on the persons with mental illness because they have no choice to perform that required guilty intention.


The architect of the law propounded various tests regarding determine the instability of the mind of the people who are committing disastrous acts without knowing the outcomes. Like The Model Penal Code test, many legendary tests, The Durham RuleThe Irresistible Impulse test, and many more, have the same uses with different technologies. 

But the M’Naughten Rule is considered one of the best methods to determine the logical thinking of the instability mind as also assured by British law. In the R vs. M’Naughten (1843) case, the English courts devised the M’Naughten test, which forms the modern-day basis of Insanity law. 

The M’Naughten Rule was established by the British House of Lords in the mid-19th century, which generally states that 

“Every man is to be presumed to be sane, and that to establish a defense on the ground of insanity, it must be proved that, at the time of the committing of the act, the party accused was laboring under such a defect of reason, from the disease of the mind, and not to know the nature and quality of the act he was doing; or if he did know it, that he did not know he was doing what was wrong.”

For better understanding, let’s take an example,

“A man murdered his family members and then waited calmly for the police to arrive. Three mental health experts testified that he was too psychologically ill and was mentally unstable during the commitment of the hurtful crime to understand that his criminal acts were wrong. He was found not guilty because of insanity and sentenced to 10 years in a mental health facility.’


  • A defendant has the legal right to plead insanity regarding the crime.
  • It creates an instant atmosphere of guilt.
  • It can lead to acquittal without receiving jail-term for longer years.
  • It does not allow the death penalty.
  • The court of justice can make a lenient on sentencing the person or send the person to the mental sentencing.


  • In various parts of the world, the insanity law is banned due to the law’s misutilization to save from harsh sentencing.
  • It can lead to high trial costs to prove the incident.
  • However, a belief circulates among the minds regards the insanity pleas are easy to access, but it is challenging to prove to the court of justice.
  • It does not have guarantee relief because if a person identified ass sane during the medical assistance will be sentenced as an ordinary accused.  


Considering various countries’ situation, the Insanity defense law has been removed by their constitution because the culprits regularly misusing the law and receiving less punishment, and can easily be out of jail. Countries such as Germany, Argentina, Thailand, some countries in England, and some states in the USA have abolished such defenses. 

Many criminals made their possible escape by initiating this defense, whether there are no specific cases regarding this defense because many countries try to hide the loophole of justice. Under the general law, it is almost impossible to prove in front of the court of law that a person is committing a crime must be mentally unstable when committing the act.


There has a modest way of determining the cases as a 17% success rate of insanity pleas in India has also been criticized. We agree that the psychiatrist as an expert witness needs to be impartial to aid the court in the delivery of justice, whereas the verdict of the lower court and the availability of sufficient evidence of suffering from mental illness before the crime is associated with the decision of the High-court in cases where there has a raised of insanity pleas.

In a present survey in the USA, it reports 26% of success rates of insanity plea in the US court of justice, and it is believed that 10% of cases had particular judgments, and the rest the 90% of people were sentenced to mental illness for proper diagnoses.  

insanity plea law in india


The subject of insanity is quite attracting the people, both in medical and legal aspects, and it is generally based upon the criminal prosecutions that the mode of its proof in a court of justice. Before the Hinckley verdict, the burden of proof in an insanity defense case has been a source of controversy. 

In Indian law, the defendant has the burden of proving the defense of insanity before the court of law by a “preponderance of the evidence,” which is similar to a civil case. And it’s a fact that a point of insanity is hard to determine and even harder to defend in the court without the proper evidence. And the burden of proving the commission of the act or crime is in the hands of the prosecution. 


This criminal prosecution of insanity plea beholds upon two aspects to prove the offense in which the top court follows (i) Commission of the act and (ii) Insanity defense.

For further reference, the court can assist psychiatrists in determining the mental health stability of the person who is necessary for the illegal act.


We do not need strict laws to govern the society against the incase criminals; there is already a law regulating the insane persons and the ordinary person. People should believe in the court of justice. Yes, there are many loopholes in which it is easy to access this defense to reduce the term of sentences for which the legal system should take of the false pleas cannot pass through the court of justice, and no dangerous person should be set free from punishments. 

Insanity plea has a modest success rate in India, and containing loopholes will diminish the whole law for which the legal system takes necessary steps to retard the consequences and hence protects the interests of the society at the same time. It is high time, whether this law is used as an excuse or not should be elevated by making some changes in the law. 


 Ratan Lal v. State of Madhya Pradesh

The appellant was caught setting fire to the grass in an open land of Nemichand. When he was asked about the act, he replied’ “I burnt it, do whatever you want” The appellant was charged under Section 435 (mischief by fire with intent to cause damage) of the Indian Penal Code the court. Regarding a psychiatrist, he was a lunatic in terms of the Indian Lunacy Act, 1912, doing insane works in an insolvent manner without having the proper knowledge. 

The trial court held that the accused was not liable to be punished under criminal law. The state filed an appeal, and the High court reversed the proceedings of the trial and held the accused responsible for the offense. Afterward, the Supreme Court allowed the request, and the conviction was set aside based upon the medical evidence provided by the doctors. These factors resulted that the accused was insolvent within the meaning of Section 84, IPC.

In the case of  Hari Singh Gond v. State of Madhya Pradesh[1], the Supreme Court observed that Section 84 of IPC sets out the legal test of responsibility in mental insanity cases. There is no definition of ‘mind soundness’ in IPC. However, the courts have mainly treated this expression as equivalent to insanity. But the term ‘insanity’ itself does not have a precise definition. It is a term used to describe various degrees of mental disorder. So, every mentally ill person is not ipso facto exempt from criminal responsibility. 

In the case of Surendra Mishra v. the State of Jharkhand[2], the court observed that every person who has a mental illness is not ipso facto exempt from criminal liability

  1. (2008) 16 SCC 109
  2. (2011) 11 SCC 495



Sanket Purohit

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