CRIMINAL LAW — Defences — Insanity — Burden and Standard of Proof
Ratio Decidendi
Per Adekeye, JSC, in Edoho v. State (2010) NLC-123-372-2007(SC) at p. 14, paras. B–E:
"The law is that in all criminal cases, every man is presumed to be sane and to possess a sufficient degree of reason to be responsible for his crimes until the contrary is proved by virtue of section 27 of the Criminal Code... Where an accused person pleads insanity or insane delusion as a defence to a criminal prosecution, there is a duty which the onus is on him to rebut the primary presumption of law as to his sanity and to establish his insanity... The standard of proof required of the accused is proof on the balance of probability or preponderance of evidence and not beyond reasonable doubt."
Explanation / Scope
This principle establishes that in criminal cases, every person is presumed sane, and the burden is on the accused pleading insanity to rebut this presumption. The standard is proof on a balance of probabilities, not beyond reasonable doubt. The principle applies where insanity is raised as a defence. It ensures that the presumption of sanity is rebutted only with sufficient proof. The principle reflects the allocation of burden in insanity defences. It prevents unsubstantiated claims of insanity. The court must require proof on the civil standard. The principle provides guidance on proving insanity.