INSANITY DEFENCE

• Date: 06 February 2019

(1) "Insanity defence" means an affirmative defence alleging that a mental disorder caused the accused to commit the crime. However, unlike other defences, a successful plea of insanity defence may not result in an acquittal but instead in a special verdict - "not guilty by reason of insanity" - this usually leads to the defendant’s commitment to a mental institution. See; Black’s Law Dictionary, Ninth Edition, page 865." - Per Ariwoola, J.S.C., in Adamu v. State Suit No. S.C. 191/2010; (2014) 10 N.W.L.R. (Pt. 1416) 441 at 466.

(2) "It is settled law that whether the accused person was sane or insane in the legal sense at the time when the act was committed is a question of fact to be determined by a jury, (Rex v. Wangara 10 W.A.C.A. 236; Walton v. R. (1978) 66 Cr. App. R 25) and not by a medical man however eminent, (R. v. Rivett 35 Cr. App. R 87) and is dependent upon the previous and contemporaneous acts of the party. (Rex v. Ashigufuwo 12 W.A.C.A. 389). Evidence of insanity of ancestors or blood relatives and evidence of illness exhausting the brain is admissible and relevant (Rex v. Inyang 12 W.A.C.A. 5). Medical evidence is admissible but not essential. In Richard Willie v. The State (1968) 1 All N.L.R. 152 this Court held that to avail himself of the defence of insanity in our law it is not sufficient for the appellant to establish that he was mentally abnormal at the time of his trial. He must go...