Legal insanity under Section 84 IPC applies when unsoundness of mind prevents knowledge of the act's nature or wrongfulness.

Section 84 IPC applies where, at the time of the act, the accused was suffering from unsoundness of mind and was incapable of knowing the nature of the act or that it was wrong or contrary to law. The governing standard is legal insanity, not merely medical insanity, and the defence must be shown on a preponderance of probabilities. The relevant inquiry is the mental condition at the time of occurrence, judged from conduct before, during, and after the . On the material described, prior treatment, chronic schizophrenia, inability to understand proceedings, and supporting medical and witness evidence established the defence, and the appellant was entitled to acquittal.

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Issues: Whether the appellant was entitled to the benefit of Section 84 of the Indian Penal Code, 1860 on the ground of unsoundness of mind and thereby to acquittal of the offence.

Analysis: Section 84 embodies the rule that an act is not an offence if, at the time of doing it, the person was by reason of unsoundness of mind incapable of knowing the nature of the act or that it was wrong or contrary to law. The governing test is legal insanity, not merely medical insanity. The burden on the accused is only to establish the defence on a preponderance of probabilities, and the relevant inquiry is the mental condition at the time of occurrence, assessed from conduct before, during and after the . The evidence showed prior treatment, chronic schizophrenia, inability to understand the proceedings, and subsequent medical and witness material supporting unsoundness of mind. The prosecution and courts below gave undue weight to the nature of the act and insufficient weight to the psychiatric evidence and surrounding circumstances.

Conclusion: The appellant was entitled to the benefit of Section 84 of the Indian Penal Code, 1860 and could not be held criminally liable for the offence.

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