A three-judge bench of justices H S Bedi, P Sathasivam and C K Prasad said the burden of proof vested on the accused to prove beyond doubt that he/she was suffering from insanity rendering him/her incapable of knowing the consequence of the action.
"The term insanity carries different meaning in different contexts and describes varying degrees of mental disorder. Every person who is suffering from mental disease is not ipso facto exempted from criminal liability.
"The mere fact that the accused is conceited, odd, irascible and his brain is not quite all right,or that the physical and mental ailments from which he suffered had rendered his intellect weak and affected his emotions or indulges in certain unusual acts, or had fits of insanity at short intervals or that he was subject to epileptic fits and there was abnormal behaviour or the behaviour is queer are not sufficient to attract the application of Section 84 of the Indian Penal Code," Justice Prasad writing the judgement said.
The apex court gave its verdict while dismissing the appeal of Surendra Mishra, a medical shop owner who shot dead at point blank range the victim Chandrashekhar Choubey on August 11, 2000 in Jharkhand.
The sessions court awarded life imprisonment to Mishra which was upheld by the Jharkhand High Court following which he appealed in the apex court claiming mentally unsoundness.
He cited Section 84 of the IPC which says, "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."
Rejecting the plea, the apex court said the accused has to "prove legal insanity" and "not medical insanity."
"Expression 'unsoundness of mind' has not been defined in the Indian Penal Code and it has mainly been treated as equivalent to insanity.
"In law, the presumption is that every person is sane to the extent that he knows the natural consequences of his act. The burden of proof in the face of Section 105 of the Evidence Act is on the accused. Though the burden is on the accused he is not required to prove the same beyond all reasonable doubt, but merely satisfy the preponderance of probabilities," the bench said