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Section 22: Act of Person of Unsound Mind

Bharatiya Nyaya Sanhita • Chapter III: General Exceptions • Official Statutory Text & Legal Guide

Chapter III: General Exceptions
Trial Court
Complete Defence
Non-Applicable
Formerly Sec 84 IPC
Section 21 All 358 Sections of Bharatiya Nyaya Sanhita Section 23

Legal Commentary & Landmark Judgments: Section 22

Section 22 establishes the defense of insanity (unsoundness of mind), codifying the historic M'Naghten Rules: 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 he is doing what is either wrong or contrary to law.

  • Legal Insanity vs Medical Insanity: The law recognizes legal insanity (total cognitive incapacity), not mere mental eccentricity, depression, or emotional instability.
  • Crucial Point in Time: The cognitive incapacity must have existed AT THE TIME of committing the act; post-crime or pre-crime mental illness is relevant only as circumstantial proof.
  • Triple Cognitive Test: Incapable of knowing: (1) The nature of the act, OR (2) That what they are doing is wrong, OR (3) That it is contrary to law.
Key Landmark Precedents:
  • Dahyabhai Chhaganbhai Thakkar v. State of Gujarat (AIR 1964 SC 1563): A landmark three-judge bench ruling: the burden of proving insanity under Section 84 IPC (Section 22 BNS) rests on the accused, but this burden is satisfied on a balance of probabilities; if the defense creates a reasonable doubt as to mens rea, the accused is entitled to acquittal.
  • Surendra Mishra v. State of Jharkhand (2011) 11 SCC 495: Reaffirmed that medical insanity is distinct from legal insanity; every person who is mentally diseased is not ipso facto exempt from criminal responsibility unless Section 84 criteria are fulfilled.
Courtroom Practice & Strategic Litigation Guidance:

To establish the defense of insanity under Section 22 BNS: (1) Lead prior psychiatric hospitalization records, (2) Prove absence of motive, (3) Show no attempt to conceal the weapon or escape, and (4) Examine the treating psychiatrist as a defense witness.

Section 21 All 358 Sections of Bharatiya Nyaya Sanhita Section 23