Not everyone who commits a crime has a criminal mind, some of them suffer from
mental illness. In Indian law, people who are suffering from mental illness or
disability are known as people of unsound mind. And the people who are of
unsound mind have certain laws or defenses in their favor. The mental health
laws in India are based on British Laws as the whole judicial system of India is
based on English common laws.
In the late 13 century complete madness
first established as a defense of criminal offense in England by common law
court and by the 18th-century madness definition evolved and insanity defense
was available to a person who was suffering from unsound of mind and unable to
understand anything or what he is doing.
According to Section 84 of Indian Penal Code:
any act done by a person who is
of unsound mind at the time of doing an act and the person is incapable of
knowing the nature of the act and the person does not know that the act which he
is doing is wrong or contrary to law.
Which means if a person in the time of
committing a crime is of unsound mind or have lack of understanding about what
he is doing then he is exempted from criminal liability. 
In one of the
landmark cases, Surendra Mishra versus State of Jharkhand
Supreme Court of
India stated that:
If the accused wants to get relief from all the liability of
his acts under section 84 of IPC he has to prove legal insanity, not medical
insanity. And The scope and ambit of section 84 of IPC came up for
consideration before the Court in case of 
Hari Singh Gond Versus State of
, (2008) it has been held that:
Section 84 lays down legal test
responsibility in cases of alleged unsoundness of mind. There is no definition
of 'unsoundness of mind' in IPC .
Now, what is legal insanity, and how it is different from medical insanity?
Actus reus and mens rea are two important and basic elements of a criminal act
and the absence of any one of them constitutes no criminal act. Legal Insanity
is mental illness or mental instability with loss of reasoning power and without
reasoning power, there is no possibility of mens rea. Medical Insanity simply
means mental illness or mental instability. Unsound mind and mental illness are
still undefined in IPC and not every person who is suffering from mental illness
or unsound mind is exempted from criminal liability.
There are various tests to prove a person legally insane, three of which are
the wild beast test, Insane Delusion, and test of capacity to distinguish right
and wrong. All these tests are laid by the Mc Naughten rule. In the 19th century
Mc Naughten killed Edward Drummond mistaking him for Prime Minister Sir Robert
Peel due to his mental illness and after hearing several medical witnesses he
testified that he is insane, he was acquitted by the house of lords and a
special committee formulated few rules for insanity as a defense and it was
called Mc Naughten rules. Even section 84 of IPC is wholly based and drafted on
Mc Naughten rule and since then no changes have been made to it till now,
despite the fact that in 1971 attempt was made by the law commission of India to
revisit section 84 of IPC.
The burden of proving an offense is always on prosecution but the burden of
proof is on the accused too if he wants to prove his insanity or elements of
section 84. 
In the landmark case of State of M.P versus Ahmadull
Court held that the burden of proof that the mental condition of accused was,
at the crucial point of time, such as is described by section, lies on the
accused who claims the benefit of this exception vide section 105 of Evidence Act [Illustration (a)]. The settled position of law is that every man is presumed
to be sane and to possess a sufficient degree of reason to be responsible for
his acts unless the contrary is proved and in the case of T N Lakshmaiah
versus the State of Karnataka, Court
under Evidence Act, the onus of
proving any of the exceptions mentioned in chapter lies on the accused though
the requisite standard of proof is not same as expected from the prosecution. It
is sufficient if an accused is able to bring his case within the ambit of any of
the general exceptions by the standard of preponderance of probabilities .
the law, it is believed that every person is sane and knows about his acts and
knows about the consequences of his actions. It is also presumed that a person
knows about laws, so the burden to prove the accused not guilty is on the
accused or his family but according to the TN Lakshmaiah case
the burden of
proof is on the accused but he is not required to prove about his insanity
beyond any reasonable doubt.
In India, 27.6% of prisoners are suffering from a mental disorder. The concept
of Insanity is huge not only in crimes but also in contracts. Making a contract
with an insane person is void in the eyes of law. Insanity law is one of the
important defenses to prove one's innocence as mental health plays a vital role
in one's life and criminal acts. Courts of India are working in insanity laws
but still definition of insanity remains undefined.
- Suresh Bada Math, Channaveerachari Naveen Kumar, and Sydney Moirangthem, Insanity
defense: Past, Present, and Future [11/11/2020 at 8:30 PM,
- Angad, Defense of Insanity [12/11/2020 at 4:00 PM], http://www.legalserviceindia.com/legal/article-3140-defense-of-insanity.html/
- Legal thirst, Indian laws for people with mental illness [12/11/2020 at
7:00 PM], https://legalthirst.com/indian-laws-for-people-with-mental-illness/.
- Surendra Mishra v. State of Jharkhand. 2011, 11 SCC 495.
- Hari Singh Gond v. State of Madhya Pradesh, (2008) 16 SCC 109 = AIR 2009
- State of M.P. v. Ahmadull,AIR 1961 SC 998
- T.N. Lakshmaiah v. State of Karnataka, (2002) 1 SCC 219