INTRODUCTION:

There is a presumption in Nigerian law that every person charged with a criminal offence is innocent until he is proved guilty.1 Therefore, a person charged with a crime is assumed to be innocent until the court decides otherwise.

In criminal trials, the prosecution presents a case against the person charged with a crime (a defendant) before a court. The law places a burden on the prosecution to prove beyond reasonable doubt that the defendant committed the crime and is guilty of an offence with which he is charged.2 Although the defendant has no obligation to prove innocence, he can put up a defence against the prosecution's case in court.

When a defendant intends to defend the prosecution's case, the defendant will enter a defence in court that provides a strategic argument against the prosecution's case. This is a criminal defence, and it is applied when the defendant's action(s) or the circumstances surrounding the crime creates an opportunity to defend the prosecution's case.

When a defendant enters a criminal defence, the burden of proof is no longer on the prosecution. This means the defendant is obligated to prove the defence. The outcome of a criminal defence may be an acquittal, or sentence reduction depending on how the defendant proves it.

In reaching a verdict against the defendant, the court relies on the prosecution evidence to convict the defendant. However, when a defendant enters defence, the court may also rely on the evidence provided by the defendant to reach a verdict.

There are various criminal defences, such as self - defence, insanity, intoxication etc.

This article will discuss the defence of insanity in Nigeria, and how it is established in a criminal trial before a court in Nigeria.

WHAT IS INSANITY?

Insanity is unsoundness of mind or lack of the ability to understand, that prevents one from having the mental capacity required by law to enter into a particular relationship, status, or transaction or that releases one from criminal or civil responsibility.3 Insanity is also defined as "any mental disorder severe enough that it prevents a person from having legal capacity and excuses the person from criminal or civil responsibility."4

The term 'Insanity' is not a medical term, but a legal standard or term which is also called legal insanity or lunacy. The term is used by lawyers and not medical practitioners.5 Insanity includes disease of the mind, congenital lack and damage resulting from traumatic injury, but excitement and obliviousness from liquor or drugs are not insanity. Insanity simply is when a person is not in the right state of mind.

There is a presumption that every person in Nigeria is sane. The law provides that every person is presumed to be of sound mind and to have been of sound mind at any time which comes in question until the contrary is proved.6 Also, under Section 43 of the Penal Code Law applicable in northern Nigeria "A person is presumed unless the contrary is proven to have the same knowledge as he would have had if he had not been intoxicated."

INSANITY AS A DEFENCE IN NIGERIA:

Everyone is responsible for his action or omission, but an insane person cannot possibly understand or control his actions, and this prevents him from acting at will or being responsible because he is unaware of his actions, omissions or the consequences.

The defence of insanity is defined in the Blacks' Law Dictionary as "an affirmative defence alleging that a mental disorder caused the accused to commit the crime." Insanity is an affirmative defence because it is brought by a defendant and not the prosecution, and when it is proved it defeats or reduces the legal consequence attached to the offence with which the defendant is charged.

Insanity is used as a defence in criminal trials, especially relating to homicide cases. Its argument is on the will of the defendant to kill the deceased. Once an insanity defence is established, the defendant is not denying the commission of the crime but is implying that a mental disorder triggered the action.

There are provisions under Nigerian law which makes insanity a defence to an offence. The Criminal Code Act 2004 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 such a state of mental disease or natural mental infirmity as to deprive him of capacity to understand what he is doing, or of capacity to control his actions, or of capacity to know that he ought not to do the act or make the omission".7 The Penal Code Law also provides that "Nothing is an offence which is done by a person who, at the time of doing it, by reason of unsoundness of mind, is incapable of knowing the nature of the act or that he is doing something that is either wrong or contrary to law"8

In criminal trials, the prosecution has no obligation to suggest insanity to the court, even if the defendant is insane. The defence is brought by the defendant, and the facts alleged in the defence differ from the facts of the prosecution's case.

Where a defendant intends to rely on the defence of insanity at his trial, when he enters the dock he must make a plea of "Not guilty by reason of insanity" which suggests to the court that the defendant is of an unsound mind. A plea of "Not guilty by reason of insanity" does not, however, automatically result to an acquittal of the defendant as he must establish it before the court. If the defendant proves it, the court will give a special verdict of "not guilty by reason of insanity" and make an order confining him to a mental facility.9

Section 28 of the Criminal Code Act, 2001 makes an exception to the defence of insanity as follows:

"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 the same extent as if the real state of things had been such as he was induced by the delusion to believe to exist."

Accordingly, if the court is not satisfied beyond a reasonable doubt that the defendant is insane or believes that the defendant is not entitled to the defence, the court will make a verdict of "guilty."

There are factors which a trial judge must take into consideration in determining the defence of insanity. These factors were stated by the Supreme Court per Ariwoola, JSC in Adamu V State as follows:

"... To constitute a defence, the mental condition relied on should be such that could and did deprive the accused of capacity: (i) To understand what he was doing; or (ii) To control his action; or (iii) To know that he ought not to do the act or make the omission complained of as constituting the actus reus of the offence charged."10

Therefore, the defence of insanity will avail a defendant where it is proved that his mental condition at the time of the offence was such that it deprived the defendant of any of the following:

  1. Capacity to understand what he was doing; or
  2. Capacity to control his actions; or
  3. Capacity to know that he ought not to do the act or make the omission complained of as constituting the actus reus of the offence charged.

A defendant who desires to rely on the defence of insanity must therefore consider if he can prove any of those three factors as it would be an exercise in futility to do so if any of those three factors cannot be proved.

ESTABLISHING AND PROVING INSANITY IN NIGERIA:

In criminal proceedings, the two ingredients used to determine if a defendant is guilty are Mens Rea (guilty mind) and Actus Reus (guilty act). These two ingredients are essential and should be present to determine a defendant's crime.

The absence of motive (mens rea) is not crucial in proving insanity. However, where there is strong evidence indicating that the defendant is not sane, lack of motive can be relevant as it cements the insanity defence.11 This means the defendant is insane, so there is no motive to kill, but it does not mean because the defendant has no motive he is insane.

In criminal trials, the burden of proof of the defence of insanity lies on the defendant. This differs from other criminal proceedings where the burden of proof lies on the prosecution. The Supreme Court per Akpata, JSC (as he then was) in Ejinima V State stated the position of the law thus:

"This is saying that the onus of proving insanity is on the defendant who should make available to satisfy the court that he was insane at the time he committed the offence. The reason is that by Section 27 of the Criminal Code Act, there is a presumption that every person is of sound mind and to have been of sound mind at any time which covers the period in question until the contrary is proved. In effect, it must be shown that the defendant at the time of killing the deceased was in such a state of mental disease or natural mental infirmity as to deprive him of the capacity to understand what he was doing or the capacity to control his action or of capacity to know that he ought not to do the act. This is made explicit by Section 28 of the Criminal Code Act"12

For the defence of insanity to avail him, the defendant has to show that he was insane at the time he committed the act.13 In Nigeria, when a defendant intends to establish the defence of insanity, there are guiding principles as follows:14

  1. Evidence on the defendant's history:
    The court will examine the defendant's past to discover facts to the claim, such as when the defendant became insane and the period of insanity.
  2. Evidence of the defendant's conduct immediately preceding the killing of the deceased:
    The actions of the defendant before the incident occurred is accessed to consider insanity.
  3. Evidence from prison warders who had custody of the defendant:
    While the defendant was detained in a prison or a cell, the prison warders who had custody of the defendant will testify and mention any abnormality noticed in the behaviour of the defendant.
  4. Evidence from medical officers who examined the defendant:
    Medical officers will examine the defendant to confirm insanity and diagnose the type of mental illness the defendant suffers.
  5. Evidence of relatives about the general behaviour of the defendant and the reputation he enjoyed for sanity or insanity in the neighbourhood:
    The defendant's relatives and individuals in the defendant's neighbourhood can also testify on the defendant's character and whether he is known to be insane.
  6. Evidence showing insanity in the defendant's family history:
    Traces of insanity in the family can confirm the defendant's claim. A person with a family history of insanity is most likely to inherit the particular type that runs in the family.

The court may accord the defendant benefit of doubt where the defendant made an attempt to establish insanity but failed and the evidence on record provided by the defendant raises concerns about his sanity in court15. The court will rely on the defendant's evidence on record, if the evidence can establish that a defendant was mentally ill when the alleged crime occurred, there will be no criminal responsibility.

This defence of insanity is upheld only when the defendant can prove that he was insane when the crime was committed.16 However, the question of fact, whether the defendant was sane or insane during the act, is for the trial Judge to determine.17

IS THE DEFENCE OF INSANITY A LOOPHOLE IN LAW ENFORCEMENT?

A loophole is an ambiguity in the law that allows people to avoid the law. Insanity has no clear definition in medical terms or legal terms, so it is a generic term that suggests any type of mental illness or mental disease. Insanity is a defence in law because it prevents the exercise of one's will.18 This defence is provided to protect mentally challenged persons who are unaware of their actions because they are mentally challenged.

The defence of insanity is trailed by controversies as it is believed that it is an escape from criminal responsibility. This defence has enabled persons who actually committed offences to escape the liability of conviction. In some jurisdictions around the world, it has gotten a lot of not guilty,19 not guilty by reason of insanity verdicts and confinement in mental institutions. Most defendants find this preferable to prison, and it has negative effects on law enforcement.

The defence of insanity should be logical in a case before bringing it as defence in court. Although the defence justifies or excuses a crime, it is not a guaranteed means to escape a criminal responsibility. Putting up this defence can be risky because once insanity is implied, the defendant admits the crime, but alleges a mental disorder prompted the crime so there should be no responsibility. When a defendant fails to prove insanity, he is convicted as a sane person and bares the usual legal responsibility. There are situations where a defendant can argue this claim and the verdict will be complex probably because of other elements which is at the Judge discretion.

Proving insanity is a bit complicated, medical evidence is essential but alteration of evidence may occur. The trial judge and not the medical doctors will determine whether the defendant was insane or not when the crime was convicted. It can be difficult to satisfy a trial judge even with all the solid evidence to prove this fact. It is risky for a defendant to raise the insanity defence merely for the purpose of obstructing justice.

CONCLUSION:

It is trite law that a mentally challenged person cannot be responsible for their actions or omissions. However, Nigerian laws presume everyone is sane, so even a mentally challenged person is also presumed sane until proven otherwise.

Insanity as a legal term doesn't refer to any particular type or stage of mental illness, so any form of mental illness is regarded as insanity in court. Thus, being mentally challenged is not sufficient proof of insanity. The judge determines the outcome of the defence and not the defence itself.

This defence is not a loophole as proving insanity is difficult, the trial Judge is not obliged to follow any medical report or result in the determination of insanity. Even if the evidence brought by the defendant is sufficient proof, the trial judge can still decide otherwise. Although, the judge is not a medical expert, and a defendant isn't expected to act like a mad person or an idiot in court, the judge may also seek expert evidence different from the one brought by the defendant. This expert evidence can assist the judge to determine the outcome of the defence.

The purpose of the defence of insanity is to protect the mentally challenged persons that live amongst us. The fact that a person who is sane can use the defence to escape criminal responsibility doesn't mean it hinders enforcement of law, besides the outcome of the defence is not acquittal.

Although the defence is rarely successful in Nigeria, the insanity test isn't tough in Nigeria. A modern insanity test set can be developed for different types of insanity claims, and these tests should involve strict approaches to test severe insanity. Different rules or elements should be in place to test different insanity claims and how it affects the capacity of the defendant.

Footnotes

1. Section 36(5), Constitution of the Federal Republic of Nigeria, 1999 (As Amended).

2. Section 135 (1), Evidence Act, 2011

3. Insanity in Merriam-webster's dictionary (11th ed.). Springfield, MA

4. Insanity in Black's Law Dictionary revised 4th edition pg. 929

5. Winfred Overholser, Psychiatry and the Law, 38 Mental Hygiene 243, 244 (1954)

6. Section 27, Criminal Code Act, 2004.

7. Section 28, Criminal Code Act 2004.

8. Section 51, Penal Code Law.

9. Adamu v. State (2014) LPELR – 22696 (SC) at page 30C – F.

10. (2014 LPELR-22696 (SC) at pages 34 – 35F - B

11. Aiworo v. State (1987) LPELR - 274 SC (Pp. 19-20, paras.G-B)

12. Ejinima V State (1991) LPELR-1067(SC) (P.21, paras. C-F)

13. Madjemu V State (2001) LPELR – 1805 (SC) at page .....

14. Udofia V State (1998) LPELR - 3305 (SC) at pages 11 - 12A – B.

15. Per Kutigi, JSC, Ntita v State (1993) LPELR-2074 (SC) (P.15, paras. E-F)

16. Ejinima V. State (1991) LPELR – 1067 (SC) at page ........

17. Rex V Wangara 10 W. A. C. A. 236 at page .........

18. Ayinde V. The Queen (1963) LPELR – 15451 (SC) at page ..........

19. Daniel M'naghten's Case10 Cl & F 200.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.