Forensic Psychiatry: Insanity Defense
From Section 84 IPC to Section 22 BNS
The defense of insanity provides immunity from criminal liability for individuals who, due to “unsoundness of mind,” were incapable of understanding the nature of their act or that it was wrong at the time of the offense.
1. Medical vs. Legal Insanity
| Type | Forensic Definition |
|---|---|
| Medical Insanity | Presence of a psychiatric disorder (e.g., Schizophrenia, Bipolar). |
| Legal Insanity | Functional incapacity to understand the nature/wrongfulness of an act at the time of the crime. |
2. Critical Forensic Criteria
- Temporal Requirement: The unsoundness of mind must exist at the exact moment the act was committed.
- Cognitive Focus: The law emphasizes the failure of the cognitive faculty (knowing right from wrong) over the volitional faculty (irresistible impulse).
- Burden of Proof: It rests on the accused to prove their insanity by a “preponderance of probabilities” (easier than “beyond a reasonable doubt”).
3. NEET PG High-Yield Pearls
- M’Naghten Rules: The foundation of Section 84 IPC; it focuses on the cognitive test of insanity.
- Irresistible Impulse: Generally not recognized as a standalone defense under Indian law (Section 84 IPC/Section 22 BNS).
- Drunkenness/Intoxication: Does not equate to “unsoundness of mind” unless it resulted in permanent/temporary insanity caused by the intoxicant.
- BNS Transition: Note that as of July 1, 2024, the Indian Penal Code (IPC) is replaced by the Bharatiya Nyaya Sanhita (BNS). Section 84 IPC corresponds to Section 22 BNS.