insanity

Section 22 BNS (old s.84 IPC) provides that nothing is an offence 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 he is doing what is either wrong or contrary to law. It is based on the M'Naghten Rules (House of Lords, 1843). The BNS keeps the phrase “unsoundness of mind”.

Only legal insanity is a defence, not medical insanity: a person suffering from a mental illness who still knew what he was doing and that it was wrong is liable. The relevant time is the moment of the act. The burden is on the accused, but only on a preponderance of probabilities; in Dahyabhai Chhaganbhai Thakker (1964) the Supreme Court held that even if he fails to prove insanity, evidence raising a reasonable doubt about his mens rea entitles him to acquittal.

Example

A man who killed his child believing he was sacrificing a goat, owing to schizophrenia, could plead insanity under s.22 BNS.

In Indian law

• Section 22, Bharatiya Nyaya Sanhita, 2023 (old s.84 IPC)
• Dahyabhai Chhaganbhai Thakker v. State of Gujarat, 1964 INSC 80

See also

general exceptions · intoxication · mens rea · burden of proof

Read more in the study notes

• Banker and customer: who they are and the legal character of the relationship (Banking Law)
• Duties of banker and customer: honouring cheques and secrecy of accounts (Banking Law)
• Kinds of accounts, opening an account, and special classes of customers (Banking Law)
• Paying banker, collecting banker and crossing of cheques (Banking Law)
• Jurisdiction in inquiries and trials, evidence, and general provisions as to inquiries and trials (Bharatiya Nagarik Suraksha Sanhita)
• General exceptions: mistake, accident, necessity and incapacity (Bharatiya Nyaya Sanhita)