The defense of insanity has become advantageous for criminals
Lakshay Parmar 4 Mar 2020

The defense of insanity has become advantageous for criminals

In the case of insanity, it is presumed that the accused suffered from severe mental instability when the crime was committed, which is why he could possibly not understand the gravity of the crime committed by him or her. In a nutshell, the individual at the time of commission of the offence was not aware of his actions due to the unsoundness of  mind or any other mental issue.


Insanity can be broadly categorized as “Medical Insanity” and “Legal Insanity”. An individual cannot be acquitted merely on the basis of ‘Medical Insanity’ and‘Legal Insanity’ must be proved to establish that the individual had no reasonable knowledge of the act he/she  has committed and its repercussions. The maxim ' actus non facet ream nisi men's sit rea ' implies that the physical act does not make a person guilty by itself, the mental component in the form of evil intent is equally important.



Modern criminal law is based on the belief that individuals are morally responsible beings and are not considered the agents that cause harm. To be held criminally responsible, two essential elements must be proven, beyond reasonable doubt,

   a. The person committed the act (actus reus)

   b. In doing so, the person acted knowingly and for rational reasons (mens rea) with his or her own free will.


Section-84 , the Indian Penal Code, 1860 (IPC) sets out the legal liability standard in cases of alleged crime committed by a person with mental illness. The IPC does not have a concept of "unsoundness of mind." Nevertheless, the courts have interpreted this term primarily as being analogous to insanity. But the word ‘insanity’ itself has no accurate definition. The term ‘insanity’holds different meanings in different ways and defines varying degrees of mental disorders. Anyone who has a mental illness is not ipso facto excluded from criminal responsibility. There needs to be a distinction between legal insanity and medical insanity.    


Historical Application

Though in the last three centuries the insanity defense has taken on a legal position, it has been in practice for decades. Various tests were used to classify a person to be legally insane, such as the Wild Beast Test, The Insane Insanity Test, and the Ability test to differentiate between right and wrong. These three experiments laid the foundation for the Mc Naughten landmark statute. The Mc Naughten statute became a groundbreaking precedent to the insanity defense rules. Section 84 of the IPC (Indian Penal Code) is based exclusively on the McNaughten rules.  The said rule follows the below mentioned principle,

"Every man is to be presumed to be sane, and ... that to establish a defense on the ground of insanity, it must be clearly proved that, at the time of the committing of the act, the party accused was laboring under such a defect of reason, from disease of 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."


In the landmark ruling of Surendra Mishra vs. State of Jharkhand (2011) 11 SCC 495, the Apex Court claimed that an accused seeking immunity from responsibility for an act under section 84 of the IPC has to prove legal insanity. It was also stated that the word "unsoundness of mind" is not specified in the IPC and hence viewed primarily as equivalent to insanity. In its judgment, the Apex Court found that although the accused suffered from certain mental instability both before and after the accident, it was not possible to infer from that due to the instability of mind  the appellant did not know the essence of his conduct at the time of the commission of the offense; that he was either incorrect or contrary to the statute, and therefore denied insanity defense.


Further, the Supreme Court in the case of Chellathurai vs The State of Madras C.P.O./T.C./I.S./D.O.No. 10/2009 has stated that the crucial time at which the instability or unsoundness of mind must be proved is the time when the crime is actually being committed and burden of proof of the same lies on the appellant to claim the defense. Under Section 84 IPC, mere abnormality of a mind or partial illusion, irresistible compulsion or compulsive behavior offers no defense.

The main purpose of the provision is fulfilled by psychiatrists who assist the court in determining whether certain mental illness or instability would affect an individual’s ability to decide what he is doing is either right or wrong or is contrary to the law.


Recent scenario and its criticism

In the recent scenario, the 2012 Nirbhaya gang rape and murder case i.e. Mukesh & Anr v State of NCT of Delhi S.L.P. (Criminal) Nos. 3119-3120 of 2014  which is still to be decided even though several death warrants were initiated but due to some or other reasons the execution order gets delayed. The counsel for the accused Vinay Sharma contented that Vinay has been continuously tortured in jail and due to that he is getting mentally unstable. Although the contention was denied by the court.


The defense by insanity is heavily criticized because of the fact that under this defense the court does not need to check whether the offence has been committed or not but has to determine the mens rea of the accused which is very complicated. Determining the mentality of the accused at the commission of the crime is a very complicated as one is judged by his acts and it is very difficult to establish someone’s intention on as the sole basis for defense to be granted.

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