The concepts “criminal responsibility” and the “Defense of Insanity” are very peculiar and important concepts in every legal system inclusive of the Nigerian legal system. Over the years, there has been much discussion on the meaning of these concepts
. The precise definition of criminal responsibility varies from place to place but, in general, to be responsible for a criminal act implies the perpetrator must understand what they are doing and that it is wrong.
This concept like most concepts operational in the Nigerian legal system today was derived from the English legal system which was predicated on common law rules and the Rules of Equity. The idea that a perpetrator of an act must understand that what he is doing is wrong is embodied in the latin maxim “actus non facit reum nisi mens sit rea” which means that the intent and the act must concur to constitute a crime. This maxim it seems made its first appearance in the common law case “LEGES HENRICI PRIMI v. 28”
criminal responsibility In Law
The Nigerian concept of criminal responsibility today is predicated on two distinct source – “The English common law and the criminal code” At common law, there is an irrebuttable presumption that practically every common law offence requires proof of quality mind but in the Nigerian legal system, the doctrine of mens rea is always a rebuttable presumption. This signifies that despite the fact that some doctrine importation has been made from the English law into the Nigerian legal system, there are some significant discrepancies between the two legal systems.
On the other hand, the origin of the insanity defense comes from the 1843 case of Daniel M’ Naghten, who tried to assassinate the Prime Minister of Britain and was found not guilty because he was insane at the time. But before the establishment of the rule in M’ Naghten’s case, other cases existed which bothered on the defense of insanity and these cases include “the trial of Edward Arnold, where it was stated thus –
“wild beast test: totally deprived of his understanding and memory, and does not know what he is doing, no more than an infant, than a brute, or a wild beast, such a one is never the object of punishment.”
The trial of James of 1800 where Thomas Erskine argued that delusion is the true character of insanity. And the case of Edward Oxford attempts to assassinate Queen Victoria, 1840- where the defendant claimed that some controlling disease was the acting power within him which he couldn’t resist. But it was in the later case of R v. Daniel M’ Nagh ten of 1843 that the standard rule of the defence of insanity was established and later cases were decided based on these rules. Much later, in 1953, the Royal Commission on capital punishment declared the M’ Naghten test of responsibility as defective and the recommendation was made to enlarge the rules by adding an exemption from responsibility in the case of one who was, by reason of his mental diseases incapable of preventing himself from committing an unlawful act.
In recognizing the place of criminal responsibility and the defense of insanity under the Nigerian legal system, S.28 of the criminal code provides that. “A person is not criminally responsible for an act or omission if at the time of doing the act or making the omission he is in a state of mental disease or natural mental infirmity as to deprive him of capacity to know that he ought not to do the act or make the omission.