Defence against insanity is used primarily in criminal prosecutions. It is based on the assumption that the defendant was suffering from severe mental illness at the time of the crime and therefore was unable to understand the nature of the crime and differentiate between right and wrong conduct, hence making them not legally accountable for the crime. The insanity defence is a legal concept, not a clinical one (medical one). This means that just suffering from a mental illness is not sufficient to prove insanity.

The defendant has the burden of proving the defence of insanity.[1]Legal insanity is hard to determine and even harder to defend it successfully in court. This research focuses on the recent Supreme Court ruling on the defence of insanity and the standards used in an Indian court. This research also covers the position of the insanity defence in other countries as well as position in India with the help of case laws.

Keywords: insanity defence, mental illness, legal insanity, medical insanity, the burden of proof.


The term “insanity” means the mental illness of such a serious nature that a person cannot distinguish between fantasy and reality, cannot manage his or her own affairs or is subject to uncontrollable impulsive behaviour.

According to the Black’s Law Dictionary, insanity means.

“any mental disorder severe enough that it prevents a person from having legal capacity and excuses the person from criminal or civil responsibility, also insanity is a legal standard and not a medical standard”.

Punishing a person who is not responsible for the crime constitutes a violation of human rights and fundamental rights under the Indian Constitution.[2] It also brings the due process of law, if that person is not in a position to defend himself in the court of law, evoking the principle of natural justice. By excusing those mentally disordered offenders whose disorder deprived them of rational understanding of their conduct at the time of the crime, the affirmative defence of legal insanity applies to this fundamental principle. Accordingly, it is generally recognized that the inability to commit crimes exempts the individual from punishment.

According to as per Black’s Law Dictionary Insanity defence is, “An affirmative defence alleging that a mental disorder caused the accused to commit the crime”.

Most of the crimes include both mens rea and actus rea, Mens Rea tells about criminal intent. In a criminal trial, the establishment of an offender’s mens rea is usually required to prove guilt. Typically, the prosecution must prove beyond a reasonable doubt that the defendant committed the offence with a guilty mindset. Mens rea allows the criminal justice system to distinguish between someone who has not intended to commit a crime and someone who has purposely set out to commit a crime.

The concurrence of a guilty mind and act constitutes a crime. (actus rea + mens rea= crime). [3]

This includes a legal maxim “Actus non facit reum nisi mens sit rea” it means the act does not makes one guilty unless he has a guilty intention.

Plea of Insanity is a plea made by the accused that he/she suffered from a mental illness during the execution of the crime and was not in a position to understand whether his act was right or wrong, thus it is said that he/she is not responsible for such an act as was not deliberately done.

Indian Law on Insanity

Insanity under IPC

The Indian law relating to insanity has been codified in the IPC section: 84 also contained the general exceptions. Section 84 of the IPC:

Acts of a person of unsound mind – “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 his act, or that he is doing what is either wrong or contrary to law”.[4]

The following principles are to be kept in mind in applying this section:

  • Any form of insanity is not legal insanity; the cognitive ability must be destroyed in order to make one unable to know the nature of his act or that what he is doing incorrect or contrary to the law.
  • The court shall presume such insanity is not present.
  • The burden of proving legal insanity rests with the convicted, even if it is not as strong as the prosecution.
  • The court must consider whether the accused suffered legal insanity at the time of the commission of the offence.
  • The circumstances that preceded attended or followed the crime are a relevant consideration in drawing such a conclusion.
  • When discharging the responsibility from the claim of legal insanity, the prosecution has merely to show the basic fact and rely on the law’s usual assumption that everyone understands the law and the natural consequences of his act.
Essential Ingredients of The Section:
  • Every act must be done by an unsound minded person.
  • Such an individual shall be unable to:
  • Understanding the act ‘s essence.
  • The act was unconstitutional.

That was the wrong act. The incapacity of the person must have existed at the time of the commission of the act

Unsoundness of Mind: It is a term that denotes lunacy and insanity. There is a legal maxim “non compos mentis” means not sane or in one’s right mind. Under the law, a person with an unsound mind is considered incompetent to go to trial. The term is used in statutes. Even after the widespread use of the term and its effects on a person’s civil and political rights, the term ‘unsound mind’ is not defined anywhere in Indian law.

Legal Insanity Versus Medical Insanity

There is no difference, in the medical sense, insanity for the purposes of criminal law. Every case of psychiatric abnormality is insane according to medical experts. According to law, not all people who are medically insane are legally insane because some of those who are medically insane are able to control and behave like normal people sometimes. His envisions the crime as an average man, and even do so with greater consideration. He knows it has been wrong with what he is doing.

We judge a man’s duty against his mens rea. Only those cases where he does not know what he is doing because of madness or he does not know what he is doing is wrong, they ‘re just excused. So only a few are legally insane among all the medically insane people.[5] In the medical field, the law proposes a different test to that.  The test in law is simply whether he is incapable of possessing mens rea because of his insanity. It is also called the ability of thought and judgment. An insane person is not punished for having any culpable mind to commit the crime.

Case Laws State of MP V. Ahamdullah [6]

Subject: The burden of proof that, at the crucial point of time, the mental condition of the accused, as described in section 84 of the IP Code, rests with the accused who claims the benefit of the exemption.

Facts: In this case, the accused had murdered his legal mother who had been ill-willed to bear in connection with his divorce. It was proven that in the night he had breached the house by climbing over the wall with the aid of torchlight and reached the room where the deceased was sleeping. All this demonstrated that the crime was committed not in a sudden mood of madness. But one that was preceded by meticulous preparation and calm calculations in execution. Directed against an individual who was considered to be his enemy. Then again, there was a mood of exultation that the accused showed after he had put out his life.

Judgement: In those circumstances, the Supreme Court rejected his plea of insanity, convicted the accused of the crime of murder (with the acquirement of both the Session Court and the High Court) and sentenced him to life imprisonment.

Ayyangar J said thus: 

In the normal case, a death sentence would have been the proper punishment for the heinous and premeditated crimes committed with human brutality. However, taking into account the fact that the accused has been absolved by the judge of the court, an order that has been confirmed.

By the high court – We find that the ends of justice will be fulfilled if we sentenced the perpetrator to life imprisonment.

Dayabhai Chhaganbhai Thakkar V. State of Gujarat [7]

In this case, the accused has been charged and convicted under the IPC, s. 302 because of the murder of his wife. The accused killed his wife with his wife by inflicting 44 knife wounds on her body. The accused brought the plea of insanity to the court of trial.

However, the trial court denied the lawsuit on the basis that the comments made to the police immediately after the incident did not demonstrate any evidence of insanity. This conviction has been confirmed by the High Court. The accused lodged an appeal with the Supreme Court. The Supreme Court has upheld the accused’s conviction and pointed out the conditions under which an accused was entitled to the defence under the law. This said that in deciding how the accused brought his case under the Indian Penal Code, 1860, s.

The court will understand the events that caused, witnessed and accompanied the criminal offence. The moment when the offence was committed is the critical period in time for assessing the accused’s state of mind. The pertinent facts are the reason for the offence, the past records of the accused’s psychiatric illness, The state of his mind at the time of the crime, and the events immediately after the incident that shed light on the state of his mind.’

Ratanlal V. State of MP 8

On 22 January 1965, the appellant set fire to the grass in the Khalyan of Nemichand. When asked why he did so, the accused said, “I burnt so; do whatever you want to do.” The defendant was arrested on 23 January 1965. He was taken to a mental hospital. The psychiatrist in the hospital confirmed that the perpetrator was mute, had a case of maniac psychotic psychosis, and needed care.

The study found the accused to be a madman under the Indian Lunatic Act, 1912 The issue before the courts was that insanity could be used as a shield against the accusation of mischief by fire with a view to causing harm under the IPC, s. It is 435. The crucial point, in this case, was whether an unsound mind could be established at the time of the commission of the act. The Supreme Court ruled that the individual was insane and absolved him.

Hazara Singh V. State of Uttar Pradesh[8]

In this case, Hazara Singh was under a delusion that his wife was unfaithful to him. One day, being disturbed by those thoughts, he caused her death by pouring nitric acid over her. Medical evidence showed that he knew what he was doing and had the ordinary knowledge of right and wrong. He was convicted of murder.

Insanity as a result of heavy intoxication

Section 85 and 86 definition

  1. IPC Chapter IV Section 85 Act of a person incapable of judgment by reason of intoxication caused against his will.– Nothing is an offence committed by a person who, at the time of the intoxication, is incapable of knowing the nature of the act or of doing what is either wrong or contrary to the law: provided that the thing that intoxicated him was administered to him without his knowledge or against his will.

Section 86. An offence requiring a particular intent or knowledge committed by one who is intoxicated.– In cases where an act is not an offence unless it is done with particular knowledge or intent, a person who acts in a state of intoxication may be treated as if he had the same knowledge as he would have had if he had not been intoxicated unless the thing that intoxicated him was administered to him without his knowledge or against his will.

Section 85 deals with involuntary intoxication. Section 86, meanwhile, regulates voluntary intoxication. Section 86 simply means that, even if the defendant is intoxicated, a person is responsible for crimes that involve specific intent or knowledge.[9] But if the individual is intoxicated against his will, no liability arises as mentioned in section 85.

There is a concept called – ‘ mens rea’ which means – a mental element of a crime – i.e. nothing is an offence if the defendant is unaware of the act and the consequences of that act.

Section-85 is intoxication to an extent by someone else that the defendant is totally unaware of the act committed by him- this is not a crime because of the complete absence of mens rea (mental element) and someone else is responsible for the circumstances.

Whereas section.86 is the same condition of intoxication but he has intoxicated himself so much so that he is unaware of his act – this is a crime because there is the intention to commit a crime and he himself is responsible for the circumstances.

The reasoning behind this is that if a person is intoxicated against her /his will or without her / his knowledge, say by mixing drinks without knowledge, because of which she/he is no longer in a position to differentiate right and wrong or legal and illegal, she/he will be deemed to not have committed a crime, because the act has been committed without the necessary mental intent, and without the knowledge of its wrongness. If, however, the person contributes in any manner to such incapacity of judgement or intoxication, then this excuse will not be applicable to her/him.

Illustration 1

Supriya goes to a party where she asks for orange juice. The bartender, for a joke, gives her orange juice with some alcohol mixed in it two or three times. not used to drinking, she does not realise this and is intoxicated upon drinking these two or three drinks. while under the influence of these drinks, she has a fight with someone at the party and shoots that person with a gun, this will not constitute a crime.

Illustration 2

Again, where Supriya herself asks for some alcoholic drinks, and when under the influence of the drinks, murdered someone. in this case, though she has committed the crime under the influence of the alcohol without realising that it is wrong, she will not be able to avail the excuse because she voluntary drank alcohol and put herself in such a situation.

‘In cases where an act was done is not an offence unless done with particular knowledge or intent, a person who does the act in a state of intoxication shall be liable to be dealt with as if he had the same knowledge as he would have had if he had not been intoxicated unless the thing which intoxicated him was administered to him without his knowledge or against his will’. If a person is voluntarily intoxicated and when intoxicated, commits such an act, then the court will ignore the fact of intoxication while determining whether or not the person had the specific intent while committing the crime.[10]

The court will deduce the persons who had specific intent while committing the crime. The court will deduce the person’s mental element from other facts. On the other hand, if the person is intoxicated against her/his will, then the court will take this fact into account while establishing the presence or absence of the specific intent required for the commission of the offence. Crimes that require specific intent, e.g. the offence of murder, means the presence of a specific state of mind.

Case laws 

Director of Public Prosecution v. Majewski[11]


Majewski went to a bar after taking different amphetamines and barbiturates, resulting in a fight with the bar owner, a customer, and the police. Majewski raised the defence of intoxication, claiming that the drugs caused him to lose control of his actions. The trial court convicted Majewski for assault and Majewski appealed to the House of Lords.

Issue. Whether voluntary intoxication is a defence to assault?

Held: Their Lordships drew a distinction between offences of “basic intent” and “specific intent” and held that in cases of the former, voluntary intoxication cannot form the basis for defence even if the intoxication produces a state of automatism. This means that a voluntarily intoxicated defendant can be convicted even where the prosecution has not proven intent.



In criminal cases, the plea of insanity as a defence has a long and fascinating history. A watershed moment in the history of the insanity defence was the adoption of McNaughten’s rules in 1843. The Indian Penal Code, the 1860s, codifies the Indian Act on Insanity. This IPC section 84 has been heavily influenced by the rules of McNaughten, and there is no other provision in Indian courts for an insanity defence. The Mc’Naughten rule requires that if a person committing a crime cannot recognize that the crime is morally or legally wrong due to mental illness or mental deficiency, then they should be found not guilty because of insanity.

Case law 

R v M’Naghten (1843) [12]


The suspect was charged with the murder of Edward Drummond, Prime Minister ‘s Secretary, Sir Robert Peel. Defender mistook Drummond for Peel and shot Drummond by mistake. He told investigators at the time of his arrest that he was going to London to kill the Prime

Minister, because “the stories in my city track and persecute me everywhere I go, crushing my peace of mind. They do everything they can to harass and persecute me.

In fact, they intend to kill me. “Defense attorneys called professionals and lay witnesses who contributed to the fascination of the defendant with paranoia and to the extreme psychosis he endured. On commission of the act in question, the judge gave the jury an instruction regarding his lack of understanding. The jury reached a non-guilty verdict due to insanity. Following

The jury was witnessed by fifteen judges at the House of Lords to decide the criteria for the prosecution of insanity.

Issue. What is the proper instruction for the jury in a case where the insanity defence is used?


Lord Chief Justice Tindal delivered his opinion to the House of Lords. Jurors would be advised to believe that any man is sane and has a reasonable degree of justification to be responsible for his crimes. Therefore, in order to create a claim of insanity, it must be explicitly shown that at the time of the crime, the accused was under such a distortion in conscience from a mental disorder that he did not know the essence and significance of the crime he was committing; even that he did not know what he was doing was false.

  1. Every man is believed to be sane and possesses a sufficient degree of rationality to be responsible for his crimes until the reverse is proven.
  2. An insane person is punishable “if he knows” at the time of the crime.
  3. To create a shield against insanity, the defendant is not in a position to know the nature and implications of his act by a defect of reason or disease of the mind.
  4. The insane person must be considered in the same situation as to responsibility as if the facts with respect to which the delusion exists were real.
  5. It was the role of the jury to decide whether or not the defendant was insane.

Competence to Stand Trial

Whether or not a defendant pleads insanity as a defence to criminal charges, at the time of trial a question may arise as to the health of a defendant. A defendant cannot be taken to court if she suffers from a mental disorder which prevents her from understanding the trials and helping prepare the defence. If a defendant asserts failure to stand trial, a judge must hold a hearing to collect testimony as to the actual jurisdiction of the defendant. In this hearing, the prosecution has the duty of showing incompetence by the predominance of the evidence to stand trial.


We conclude that In India, insanity defence, Section 84 IPC is solely based on the Mc Naughten rules and no changes so far have been made since it is drafted. punishing a person who is incapable of knowing the nature of his act constitutes the violation of his fundamental rights. Legal insanity applies when the defendant had no knowledge of his actions or what he is doing right or wrong, by taking the defence of insanity the defendant exempts from there liability. The burden of proof is on the defendant and he must prove that he was ill at the time of the crime. Intoxication under insanity is not so much of a defence but more of a denial of mens rea.

The defence can only be relied on if the consequences of intoxication cause the defendant to lack the capacity to form the required malice intention. If there is an intention of causing harm the defendant will not escape from the liability. Defendant cam found both guilty and insane the reason behind this defendant’s sanity is not determined until after a defendant has been found guilty of a crime. Then, if a defendant is found to have insane when a crime was committed, the defendant is placed in a mental hospital. If the defendant’s sanity is restored, the defendants go to prison to serve any remaining time on the sentence.


apoorvaApoorva Katare


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  2. Ratanlal – Dhirajlal’s Indian penal code.
  3. D. Gaur’s Criminal law: Cases and materials, Butterworths, India.
  4. Srivastava, O.P., Principles of Criminal law, 4th edition,2005.
  5. RP Kathuria, “Supreme court or criminal law”, Volume 3, 5th edition, 1996.
  6. KSN Murthy and KVS Sharma, “Criminal law”, 1st edition, 2001.
  7. ND Basu, “Indian Penal Code”, 29th edition, 2006.
  8. Gandhi, “Indian Penal Code”, 2nd edition, 2006, at pp.125.
  9. Huda: The Principles of the Law of crimes in British India, (1982).
  10. Christopher Slobogin, An End to Insanity: Recasting the Role of Mental Disability in criminal cases, SSNN No, 2567135.
  11. Punishment or Treatment? – Comparing the Lengths of confinement of Successful and Unsuccessful Insanity.
  12. Braff, J., Arvanties, T., and Steadman, H.J. (1983). Detention patterns of successful and unsuccessful insanity defendants. Article no. 21, pg. 439-448.
  13. Silver, E., Ciricione, C., & Steadman, H.J. (1994). “the insanity defence: A closer look”.
  14. “The role of criminal intent and insanity in our legal system”., By Candace Butera.,2018.
  15. “Criminal Law Journal” Chief Editor: V.R. Manohar, Advocate., Vol.125-part 1439.

[1] Bishop criminal law in Basu’s Indian penal code, 12th ed., 2016, vol.3, pp. 267

[2] B.M. GANDHI, ‘INDIAN PENAL CODE’, 4th ed., 2018 at pp.127

[3] Christopher Slobogin, An End to Insanity: Recasting the Role of Mental   Disability in criminal cases, SSNN No, 2567135.

[4] The Indian penal code, 1860 by universal law publishing, 2017, pp. 08

[5] Hari Singh Gond v. State of Madhya Pradesh. 2008, 16 SCC 109.

[6] State of M.P. v. Ahmadullah. AIR 1961 SC 998

[7] Dahyabhai Chhaganbhai Thakker v. the State of Gujarat. 1964 AIR 1563, 1964 SCR (7) 361 8 Ratan Lal Vs. State of Madhya Pradesh. 1970 (3) SCC 533.

[8] Hazara Singh V. State of Uttar Pradesh AIR 1969 SC 951,

[9] K.D. Gaur, The Indian Penal code, ed.,2019, pp.376

[10] A.P. Bhardwaj, LA&LR, ed.,06, pp. 3.231

[11] Director of Public Prosecutions v. Majewski, 2 All E.R. 142 (H.L. 1976).

[12] R v M’Naghten (1843) 8 ER 718, Volume 8


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