THE MEANING AND NATURE OF THE DEFENCE OF INSANITY
According to the Blacks Law Dictionary, insanity is any mental disorder severe enough that it can also be said to mean the state of being seriously mentally ill.
The defense of insanity comes in where an individual is unable to detect the wrongfulness or rightness of his action. This defense is an affirmative defense alleging that a mental disorder caused the accused to commit the crime unlike other defenses, a successful insanity defense results not in acquittal but instead in a special verdict (“not guilty by reason of insanity”)
DEFENCE OF INSANITY and Our World
The defense of insanity basically reflects the society’s belief that the law should not punish defendants who are mentally incapable of controlling their conduct. it has for entries been recognized that if a person was, at the time of his unlawful act, mentally so disordered that it would be unreasonable to impute guilty on him, he ought not to be held liable for conviction and punishment.
The first famous test for defense of insanity as earlier stated in the chapter one of this work was first initiated in the chapter one of this work was first initiated in the English case of Daniel M’ Naghten 1843 where the presiding judge, lord Tindal stated that the question to be asked is whether the prisoner had or has not the use of his understanding, so as to know that he was doing a wrong and wicked act.
The accused was acquitted on the basis of not guilty by reason of insanity. This led to the issue of insanity being debated in the House of Lords. As a result, five questions were put to the judge the answers to questions two and three form the basis of the “M” Naghten rules” by which lack of criminal responsibility is tested. And these questions are as follows as delivered by Lord Tindal C.J.
“…What are the proper questions to be submitted to the jury, where a person alleged to be afflicted with insane delusion respecting one or more particular subjects or persons, is charged with the commission of crime, and insanity is set up as a defense? And, thirdly in what terms ought the question to be left to the Jury as to the prisoner’s state of mind at the time when the act was committed?”7
In recognizing the place of the defense of insanity under the Nigeria legal system, section 28 of the criminal code or omission he is in such a state of mental disease or natural mental infirmity as to deprive him of capacity to understand what he is doing, or capacity to control his actions, or of capacity to know that he ought not to do the act or make the omission.
A person whose mind, at the time of his doing or omitting to do an act is affected by delusions on some specific matter or matters but who is not otherwise entitled to the benefit of the foregoing provisions of this section, is criminally responsible for the act or omission to same extent as if the real state of things has been such as was induced by the delusions to believe to exist.
a) To understand what he was doing; or Morgan, J. while making reference to verity CJ’s judgment in the case of OMNI defined the words “Natural mental infirmity” as a defect in mental power neither produced by his own default nor the result of disease of the mind. However, mental infirmity which is self induced is not natural and is not a defense of insanity under the provision o f section 28 of the criminal code. More so, section 27 of the criminal code provides that every person is presumed to be of sound mind, and to have been a sound mind at any time which comes in question, until the contrary is proved.
It was also held Per Onu, J.C.A. that the duty to decide whether the appellant is of unsound mind or not is that of the trial judge who by law is not bound by the certificate of the medical officer to the contrary although naturally, great weight ought to be attached to the medical opinion.
Under the Nigerian legal system, certain rules have been laid to help ascertain the soundness or unsoundness of the mind of the accused. These rules were laid down by verity C.J in the case of Rex V. Omoni and they are as follows. First, it must be shown that the prisoner was, at the relevant time, suffering either from ‘mental disease’ or from ‘natural mental infirmity’ as we have interpreted its meaning. Then it must be established that the mental disease, or the natural mental infirmity, as the case may be, was such that, at the relevant time, the prisoner was, as a result deprived of capacity.
b)To control his actions, or
c) To know that he ought not to do the act or make the omission.
It must further be remembered that if the defense be one of partial delusion, the provisions of the second paragraph to section 28 of the criminal code are applicable and that they are similar to the rules in M’ Naghten’s case as to delusions.
The key element of the defense of insanity is the admission by the appellant that he committed the offence but that his liability ought to be mitigated by reason of insanity.