BNS Section 22: Act of a person of unsound mind (2026)
What Section 22 of the Bharatiya Nyaya Sanhita (BNS) says about an act done by a person of unsound mind, how it maps to Section 84 of the IPC, and the test courts apply for the insanity defence. Last verified October 2026.
Explainer · Criminal Law · BNS
Section 22 of the Bharatiya Nyaya Sanhita (BNS) is the insanity defence. It says that nothing is an offence which is done by a person who, at the time of doing it, by reason of unsoundness of mind, cannot know the nature of the act, or that it is wrong or contrary to law. Section 22 replaced Section 84 of the Indian Penal Code (IPC) from 1 July 2024. This explainer sets out the test, how it maps to the old law, and how courts apply it. Last verified October 2026.
- New section: the insanity defence is Section 22 of the BNS, in force since 1 July 2024.
- Old section: it replaced Section 84 of the IPC. The test is unchanged.
- Test: by reason of unsoundness of mind, the person was incapable of knowing the nature of the act, or that it was wrong or contrary to law, at the time of the act.
- Burden: the accused must prove the defence on the balance of probabilities. It is legal, not merely medical, insanity.
01Why the defence matters
Criminal guilt needs a guilty mind. If a person cannot understand what he is doing because of a serious mental illness, punishing him serves no purpose. Section 22 of the BNS recognises this. It is the legal defence of unsoundness of mind, often called the insanity defence.
Since 1 July 2024 the Indian Penal Code (IPC) is replaced by the Bharatiya Nyaya Sanhita, 2023 (BNS). The old Section 84 rule now sits in Section 22. The test is carried over, so if you earlier cited "Section 84 IPC", you now cite Section 22 of the BNS.
02What Section 22 says
Section 22 of the BNS reads, in substance: 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 the act, or that what he is doing is either wrong or contrary to law.
This is a general exception. It does not create an offence and carries no punishment. It admits that the act was done, but removes criminal liability because the person could not understand it. The key moment is "at the time of doing it", so the inquiry is about the accused state of mind during the act, not before or after.
Legal insanity, not medical illness
Section 22 is about legal insanity, which is narrower than medical illness. A person may have a mental illness and still be liable, unless the illness made him unable to know the nature of the act, or that it was wrong or unlawful.
03The test for unsoundness of mind
The defence works only if, because of unsoundness of mind, the person was incapable of at least one of the following at the time of the act:
- knowing the nature of the act; or
- knowing that the act was wrong; or
- knowing that the act was contrary to law.
A mental illness alone is not a defence. The illness must have made the person unable to know the nature of the act, or that it was wrong or unlawful.
This is a high bar. The burden of proof lies on the accused to show, on the balance of probabilities, that the defence applies. The prosecution still has to prove the offence itself beyond reasonable doubt, but the plea of unsoundness is for the defence to make out.
04Old to new: IPC 84 to BNS 22
Section 84 of the IPC is now Section 22 of the BNS. The test and the wording are carried over, so the settled case law on Section 84 still guides how Section 22 is read.
| Point | Old law (IPC) | New law (BNS) |
|---|---|---|
| Act of a person of unsound mind | Section 84 | Section 22 |
| Nature | General exception | General exception |
| Test | Incapable of knowing nature, or that act is wrong or unlawful | Same test carried over |
Because the rule is unchanged, decisions on legal insanity decided before 1 July 2024 remain good law. The main change is the section number.
05How courts apply it
Courts treat unsoundness of mind as a question of fact. The accused must place material on record, such as medical history, conduct before and after the act, and expert evidence. The court then decides whether, at the moment of the act, the accused could know its nature or that it was wrong or unlawful.
Section 22 is one of the general exceptions, alongside defences such as involuntary intoxication under Section 23 and the act of a child under seven under Section 20. Each removes criminal liability because of the state or capacity of the person who did the act.
06Where Claw fits
Claw is an all-in-one legaltech platform for Indian advocates, law firms, and corporate legal teams, combining AI-based case search, an AI legal assistant (Legal GPT), case management, and compliance automation across all Indian courts and tribunals.
The insanity defence lives or dies on how courts have weighed similar facts, so you need comparable judgments fast. Claw holds more than 30 crore judgments and returns each search in under 5 seconds, so you can read how a court has applied the old Section 84 or the new Section 22, or follow a pending plea through its hearings and orders across the 9,102 courts, benches and forums it tracks.
Claw does not use customer case documents to train its AI models. Open a free Claw account to trace an unsoundness-of-mind matter by party or by the advocate arguing it, and to watch it as it is heard. For the wider search across the whole of reported law, see case search across Indian courts.
07Sources and further reading
- India Code (official text of the BNS, 2023): indiacode.nic.in
- PRS Legislative Research (BNS overview and IPC comparison): prsindia.org
- Section 22, BNS (bare text): devgan.in
- Claw: clawlaw.in
This explainer is general information, not legal advice. The law changes through amendments and judgments, so check the current text and take advice from counsel before you act.
08Frequently asked questions
What is Section 84 IPC in the BNS?
Section 84 of the IPC, the defence of unsoundness of mind, is now Section 22 of the Bharatiya Nyaya Sanhita, 2023. The test is carried over: the act is not an offence if, by reason of unsoundness of mind, the person could not know its nature, or that it was wrong or contrary to law.
Is any mental illness a defence under Section 22?
No. Section 22 requires legal insanity, which is narrower than medical illness. The illness must have made the person incapable, at the time of the act, of knowing the nature of the act, or that it was wrong or contrary to law.
Who has to prove the insanity defence?
The accused. The burden is on the defence to prove unsoundness of mind on the balance of probabilities. The prosecution must still prove the offence itself beyond reasonable doubt.
What moment does the court look at?
The time of the act. Section 22 asks whether, at the moment the act was done, the person could know its nature or that it was wrong or unlawful. The state of mind before or after is only relevant as evidence of that moment.
Does old case law on Section 84 still apply?
Yes. Because the test and wording are carried over into Section 22, judgments on Section 84 of the IPC still guide how courts read the insanity defence under the BNS.
Can I track a case involving Section 22 in Claw?
Yes. You can look up a Section 22 plea by party or advocate and keep its orders and hearings in view across the 9,102 courts, benches and forums Claw covers, with more than 30 crore judgments behind each search and results in under 5 seconds. Claw tracks and researches the matter but does not give legal advice.