In NWOYE IGWEZE ONYEKWE v. THE STATE (1988) LPELR 2732 (SC), this Court detailed some of the guiding principles in establishing insanity viz: 1. Evidence as to the past history of the accused. 2. Evidence as to his conduct immediately preceding the killing of the deceased. 3. Evidence from Prison Warders who had custody of the accused and looked after him during his trial. 4. Evidence from Medical Officers and/or Psychiatrists who examined the accused. 5. Evidence of relatives about the general behaviour of the accused and the reputation he enjoyed for sanity or insanity in his neighbourhood. 6. Evidence showing that insanity appears in the family history of the accused. See also UDOFIA v. STATE (1988) LPELR 3305 (SC).
WHAT IS REQUIRED TO PROVE INSANITY
In order to succeed in a plea of insanity, the Appellant must before the trial Court, prove on the balance of probability that as at the time of committing the offence, he lacked the capacity to; 1. Understand what he was doing 2. Control his actions 3. Know that he ought not to act or make the omission See BABANGIDA JOHN v THE STATE (2012) 7 NWLR (PT 1299) 336.
– Abdu Aboki, JSC. Chukwu v. State (2021)