The law is settled that the burden of proof of insanity lies on the accused person. In NDU v THE STATE 1990 LPELR-1975 SC this Court held as follows: The law is that the burden of proving insanity rests on the accused person. Of course the burden of proof which he has to discharge is a light one. It is a proof by a preponderance of evidence or on a balance of probability. The defense of insanity is a plea which must be positively put forward by way of defence and evidence should be adduced in support.
– Abdu Aboki, JSC. Chukwu v. State (2021)