Is the Insanity Defence Used as Loophole for Criminals?

The plea of insanity in criminal defence has had a fascinating and long journey. Punishing a person, who is not responsible for their actions goes against both basic human rights as well as the fundamentals of the Constitution of India. Therefore, the defence of legal insanity appeals to the fundamental principles and excuses those who at the time of commitment of the crime was not aware of their actions and therefore, cannot be held responsible for the crime. It directly falls under the wing that the accused did not have Mens rea even though they did commit the actus reus. However, to avail this defence where an accused gets acquitted after admitting guilt, it needs to be proved beyond doubt by the most distinguished and unquestionable evidence that the criminal was incapable of judging whether their action was right or wrong. Therefore, just being clinically insane is not enough to get excused, it must be a person so deprived of their understanding and memory that they cannot be held more accountable than a wild animal or an infant can be for their actions.

The insanity defence more often than not is taken as an excuse for committing the crime rather than justifying the acts. Throughout history, there have been numerous tests to declare a person insane like Wild Beast test, The Insane Delusion Test, The test of capacity to distinguish between just and unjust[1] etc. until the M’Naghten case came into existence.

In India, sec 84 deals with “person of unsound mind” and explains quite sufficiently the burden of proof, the difference of medical and legal insanity, the definitions of various terms, the role of a psychiatrist and gives illustrated examples of cases and articles.

In India, Section 84 of the Indian Penal Code talks about the act of “a person of unsound mind” and discusses insanity as a plea of defence. It states that nothing is an offence 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 something that is either wrong or contrary to law.[2] Under this section, judgements have been passed in this country acquitting the guilty who have proved their insanity. According to 2019 data, 76.50% of cases where the insanity plea was raised was murder.[3]

Insanity is usually pled in criminal cases (most commonly murder) where the burden lies upon the defendant to prove that they were suffering from severe mental illness and thus were unable to assess the nature of the crime.

This insanity plea has come into existence by basically following two fundamental maxims of criminal jurisprudence

  1. Actus non facit rea mens sit rea which translates into an act does not constitute guilty unless it is done with a guilty intention.
  2. Furiosi nulla voluntas est which says that a person with mental illness has no free will.[4]

David Bazelon said that “collective conscience does not allow punishment where it cannot impose blame”.[5] So, it is established that a mentally unstable person cannot be held criminally liable because they were not aware of their actions or their crimes.

The insanity though needs to be legal and not medical. Now the main difference between legal and medical insanity is that medically a person can be declared to be suffering from mental illness but that is not enough for the guilty to get acquitted. To prove legal insanity, the defendant needs to prove that in addition to being medically insane the person has also lost their power of reasoning and most importantly, thus, were not able to realise what they were doing or whether the deed committed was wrong at the moment of the crime. The High court of Madras agreed to this fact when they rendered their judgement which said that to avail the defence of insanity the crucial point of time that needs to be taken into consideration is the material time when the offence takes place.[6]

Therefore, while proving legal insanity, the defendant needs to prove that they were not in a sound state of mind during the commitment of the crime.

 Insanity is usually of two kinds

  1. Temporary insanity where the person is insane only temporarily or for a particular time duration. The diseases under this category include schizophrenia, anxiety disorder, depression and others. Here the defendant can either plead not guilty because insane or guilty but cannot be punished because insane.
  2. Permanent insanity where records and events can prove mental insanity and thus the defendant can show that he was not in the correct state of mind to assess his actions or know whether they are right or wrong.

M’Naghten Case

The test of mental insanity was first taken into consideration in the historic M’Naghten case in 1843, which is a landmark decision on insanity as a defence in English criminal jurisprudence.[7] Before that, the Hadfield case which led to the criminal lunatics’ act of 1800 was held to be a landmark case in this field and was the first to consider insanity as a special verdict. Then came this case which led to the establishment of the M’Naghten rules which then became the basis of Section 84 of Indian Penal Code[8].

The answers given by the judges in the M’Naghten case may be summarised in the following five rules:-

  1. That every man is presumed to be sane, able to understand the effects of the crimes and have enough reason to be held responsible for the crimes they have committed unless the defendant proves anything to the contrary.[9]
  2. To plea the insanity defence in the court of law it needs to be proved that the accused, due to the defect of mind was unable to see reason and therefore not realise the nature and quality of the act he committed and even if he did, not know that the act he was doing is wrong.[10]
  3. If the previous rule does not apply then the accused should not have been aware that the act he committed was something he should not have done and that if the act committed was contrary to the law of the land, he was punishable.[11]
  4. Whereas criminal act is done by a man under some insane delusion as to the surrounding facts, which conceals him from the true nature of the act he is doing, he will be under the same degree of responsibility as he would have been on the facts as imagined them to be.[12]
  5. A medical witness who has not seen the accused before trial should not be asked on the evidence whether he thinks that the accused was insane.[13]

When an accused fall into either of these categories they are considered to be eligible for the insanity plea and are not held liable for the crime they have committed. They are usually acquitted but that does not necessarily mean that they go free.

Now, as soon as the defendant takes insanity as a defence it leads to a few conclusions

  1. Guilty – to take the insanity defence the accused needs to accept that he is guilty of the crime committed. This is one of the advantages of the insanity plea. It proves that the accused has actually committed the crime and is not asking to be excused but instead holding himself unaccountable for the crimes they have committed.
  2. Misuse – The insanity plea can often be misused as it is very difficult to prove that the person was not of sound mind during the exact time the crime was committed. It is left up to the judge to assess and analyse whether the accused should be granted the plea or be punished for his deeds. This is usually very tricky as it is both extremely unfair to put an innocent behind bars and every person not responsible for the crimes they have committed are innocent. Again, if the guilty are using the insanity plea as a loophole to get out of the punishment for their crimes they should be punished. 
  3. Punishments – The accused is never given the death penalty and is often acquitted when proved insane. (This does not necessarily mean that the accused goes free. Each state usually has its guidelines for dealing with mentally insane criminals. They are usually sent to psychiatric facilities where they often stay as long as would have been termed for and sometimes even longer varying from state to state). On one hand, the judiciary is faced with a person who has violated the law of the land and therefore poses a threat to society. On the other hand, it is not morally appropriate to punish a person unaware of his crimes.

Due to these dicey situations, several jurisdictions have abolished the plea of insanity and now to avail the plea the accused needs to be transferred to a different jurisdiction.

Role of a Psychiatrist

The psychiatrist can either be the usual doctor of an accused asking for the insanity plea or a court-appointed doctor to assess the accused ideally from the beginning of the trial. But the common involvement of psychiatrist takes place when they are consulted to evaluate the criminal as well as the nature of the crime committed.

It is necessary to do a standard evaluation of every criminal who pleads insanity. The psychiatrist also asks for previous certificates proving insanity. They assess the history of the prevailing mental illness as well as gives careful focus on the examination of mental illness at the time of the crime. 

Though the psychiatrist ideally starts assessing the criminal from the beginning of the trial, since the law believes every person to be sane until the contrary is proven, they are asked to hold on making definitive diagnosis initially. Such necessary steps make these trials extremely expensive as an expert needs to be consulted almost around the clock.

But that is not always the case as negligence runs deep in the judiciary system too. In 25.49% cases, no psychiatrist was consulted before finalizing the cases and therefore the details were not clear.[14] In such situations, it is very hard to correctly conclude whether the accused deserves to be acquitted or not.


The most common crime where the insanity defence is pled is murder. In quite a few of these cases expert opinion was not even taken into account. So even though the insanity plea leads to the accused admitting guilt it is becoming more and more common for them to do to leads to milder punishments and even acquittal in some cases. Therefore, quite expectedly, the insanity plea is becoming very popular among criminals to get out of punishments.

Even though we have a set of guidelines to determine whether a person deserves the insanity plea, criminals are become more and more intelligent with the passing day and are finding loopholes to avert any judgement which will not be in their favour. The recommendations of the 42nd Law Commission of India were not incorporated in the IPC. They decided that the present provisions were enough and there was no need to make the rules more stringent or flexible.

Moreover, mere arguments are not enough to decide whether a person, who was not aware of their actions while committing them, deserves to be punished. So, a typical black and white case turns into a grey area and it becomes very difficult for the judge to determine the mental status of the defendant at the time the offence took place as well as the circumstances under which they took place.

Again, it has to be argued that whenever anyone pleads the defence of insanity they are put under a microscope and their past, present and future are very well scrutinised. So, it is extremely difficult to take the defence of insanity falsely as it is more likely to come out in court than not, and even when the person is acquitted they often are referred to a psychiatric facility where they stay for a long period which cannot exactly be termed as an acquittal.

[1] Parathaswamy Ramamurthy, Vijay Chathoth, Pradeep Thilakan, how does India decide insanity pleas?  A review of high court judgements in the past decade, Indian Journal of Psychological medicine (serial online) (March, 2019, 10:05 A.M.),

[2] Indian Penal Code, 1860, No. 4, § 84.

[3] Parathaswamy Ramamurthy, Vijay Chathoth, Pradeep Thilakan, how does India decide insanity pleas?  A review of high court judgements in the past decade, Indian Journal of Psychological medicine (serial online) (March 2019, 10:05 A.M.),

[4]Suresh Bada Math, Channaveerachari Naveen Kumar, Sydney Moirangthem, Insanity Defence: Past, Present and Future, Indian Journal of Psychological Insanity (October, 2015, 11:22 A.M.),!po=65.0000.

[5] American Bar Association Criminal Justice Mental Health Standards, 1986, pg 324.

[6] Chellathurai vs State, (2011) 3 SCC (Cri) 473.


[8] Kalicharan V. Emperor, AIR 1948 Nag. 20 (2).

[9] State V. Lilanand Pathak, 1977 Cri. L.J. 513.

[10] Gopal V. State of Rajasthan, 1984 Cr. L.J. 874.

[11] 1976 Cri.L.J. 1978.

[12] Ram Lai V. State of Rajasthan, 1977 Cri. L.J. (N.C.) 168 Raj.

[13] R.C.Nigam, Law of crime in India, Vol. I, (1965) PP. 362-363.

[14] Parathaswamy Ramamurthy, Vijay Chathoth, Pradeep Thilakan, how does India decide insanity pleas?  A review of high court judgements in the past decade, Indian Journal of Psychological medicine (serial online) (March, 2019, 10:05 A.M.),

Aishani Chakraborty from Damodaram Sanjivayya National Law University, Visakhapatnam

Aishani is a first year law student and aspiring lawyer. She loves writing about prevalent socio-legal issues and other legal topics.” 

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