Authored By: VIDHYASRI A/ P SANTHIRAN
UNIVERSITI UTARA MALAYSIA
INTRODUCTION
“Sometimes it’s the people who no one imagines anything of who do the things that no one can imagine” – Alan Turking
In moments of intense frustration, one might fleetingly imagine escaping the consequences of a grave act by simply feigning mental illness. Popular portrayals, such as in Primal Fear, reinforce the notion that the defence of insanity can be easily manipulated to evade criminal liability. But does the law truly permit such a convenient escape? The perception in the defence of insanity has led to a widespread belief that individuals can simply feign mental illness to avoid conviction. However, such assumptions overlook the stringent legal and procedural safeguards governing the application of the insanity defence within the modern criminal justice system.
Historically rooted in English common law, the doctrine was crystallised in M’Naghten’s Case, which established the foundational principles for determining criminal responsibility in cases involving mental incapacity. These principles have significantly influenced jurisdictions such as Malaysia, where the defence of insanity is recognized under statutory law and applied within a strict evidentiary framework. Despite its longstanding legal basis, the defence continues to attract criticism and misunderstanding, particularly regarding its perceived function as a “legal loophole.”
This article then examines whether the defence of insanity in Malaysia operates as a genuine loophole that enables offenders to evade justice, or whether it is, in reality, a narrowly confined legal doctrine subject to rigorous judicial scrutiny. It argues that the insanity defence does not provide an easy escape from criminal liability but instead imposes a high evidentiary burden on the accused, requires comprehensive medical and legal evaluation, and often results in compulsory confinement rather than outright acquittal.[1]
In order to support this argument, this discussion proceeds in three parts. First, analyse the stringent legal requirement necessary to establish the defence, particularly the burden of proving the accused’s mental state at the time of the offence. Secondly, it evaluates the legal consequences of a successful insanity plea, emphasising that such outcomes prioritise institutionalisation and public safety over personal liberty. Finally, it considers the rarity and strict judicial control of the defence in practice, demonstrating that it is neither easily invoked nor readily accepted by the courts. Through this analysis, the article seeks to dispel misconceptions and affirm that the insanity defence functions as a controlled legal safeguard rather than a loophole within the Malaysian criminal justice system.
ARGUMENTS ON WHY LEGAL INSANITY IS NOT A LEGAL LOOPHOLE
INSANITY IS A COMPLEX AND STRINGENT DEFENCE THAT REQUIRES SUBSTANTIAL EVIDENCE
The first argument which proves that the insanity defence cannot be classified as a legal loophole is that it is a complex and stringent defence that requires substantial evidence to prove the defendant’s mental state at the time of the crime.[2] The Oxford Dictionary defines insanity as being insane or mentally ill.[3] However in law, the term “insanity” refers to a legal condition rather than a medical one. It concerns a person’s incapacity to distinguish between right and wrong or understand the nature of their actions at the time of the offence.
At the moment of the crime, the accused must have been so impaired that their cognitive abilities were affected to the extent that they could not comprehend what is true or false. In extreme cases, the impairment may be so severe that the person cannot even determine the nature of their act. For instance, not knowing whether they are holding a knife or a gun. While this may sound unbelievable, such conditions do exist, and the law must address them carefully to ensure proper remedies for such serious situations.
In Malaysia, the insanity defence is recognised as the defence of unsoundness of mind under the Malaysian Penal Code. This defence is governed by Section 84 of the Penal Code,[4] which provides that an act is not an offence if, at the time it was committed, the person was incapable of understanding the nature of the act due to mental illness, or of knowing that the act was wrong or contrary to law. This means that the accused may be acquitted if it can be proven that, at the time of the offence, they were mentally impaired and lacked mens rea.
However, proving insanity is far from easy. The general principle is that every person is presumed to be sane unless proven otherwise. Therefore, the burden lies on the accused to plead and establish insanity in court. The court will not raise it on its own. This highlights the strict application of the defence.[5]
This principle is illustrated in the case of John Nyumbei v Public Prosecutor,[6] where the court emphasised that the defence of legal insanity relies heavily on evidence. The accused must first prove, as a preliminary issue, that he was of unsound mind at the time of the act. Even if this is established, he must further prove that the degree of unsoundness of mind was so severe that it deprived him of basic cognitive skills. The court will closely examine all material evidence to determine whether the accused is legally entitled to rely on Section 84 of the Penal Code.[7]
In the researcher’s view, John Nyumbei is a strong authority because it not only highlights the importance of evidence but also sets out the strict requirements that must be satisfied before the defence can succeed. While evidence can be gathered with effort, the real issue is whether such evidence meets the level of validity and authenticity required by the court. The reality is that it is extremely difficult for a sane person to convincingly fake insanity throughout the entire legal process. Criminal trials involve intense investigations, psychiatric evaluation, and rigorous cross-examination. As a result, the likelihood of successfully abusing this defence is very low.
This strict approach is further supported by cases such as Sinnasamy v Public Prosecutor[8] and Kenneth Lee Fok Mun case.[9] In Sinnasamy, the accused claimed he killed his daughter during an epileptic fit, supported by medical evidence that epileptic patients may be unconscious during episodes. In Kenneth Lee, the accused argued that his actions were caused by hypoglycemia. In both the cases, the defence of automatism was raised but ultimately failed. A closer look at these cases shows why the defence is so difficult to establish. In Kenneth Lee, the presence of a weapon suggested intention. In Sinnasamy, the nature and severity of the injuries indicated that the accused must have been conscious while inflicting them. These examples demonstrate that courts carefully scrutinise every piece of evidence before accepting such a defence, ensuring that it cannot be easily misused.
Furthermore, an important point to be noted is that not all forms of mental illness qualify as legal insanity.[10] The accused must prove that the condition amounts to legal insanity, not merely medical insanity. This distinction is well established in Hari Singh Gond v State of Madhya Pradesh,[11] where the court held that not every mentally ill person is exempt from criminal liability. While medical evidence may be relevant, the court ultimately focuses on whether the legal test for insanity is satisfied.
To summarise, in order to succeed under Section 84 of the Penal Code, three key elements must be established. First, the accused must prove that at the time of the act, they were suffering from unsoundness of mind. Second, this condition must have impaired their cognitive abilities. Third, the impairment must have rendered them incapable of understanding the nature of their act.
INSANITY DEFENCE OFTEN RESULT IN THE DEFENDANT BEING COMMITTED TO A MENTAL HEALTH FACILITY RATHER THAN BEING SET FREE
The second argument is that a successful insanity defence does not result in the defendant being set free, but instead leads to confinement in a mental health facility, with a focus on rehabilitation rather than punishment. This is because they require medical attention and structured care to recover, rather than mere imprisonment. Nevertheless, public concern regarding the possibility of such individuals being released back into society is understandable. To address this concern, it is important to examine the legal safeguards in place in Malaysia. Pursuant to Section 347 of the Criminal Procedure Code (CPC),[12] after evaluating all the evidence, if the court finds that the accused is not guilty by reason of unsoundness of mind, the accused will not be released but instead placed in appropriate custody. Further, under Section 348(1) of the CPC,[13] the court must ensure that the accused is kept in safe custody in a manner that it considers fit, and the matter must be reported to the Ruler of the State.
Although the CPC does not specifically outline the rehabilitation process, this is governed by the Mental Health Act 2001 (MHA),[14] which regulates the admission, detention, and discharge of mentally ill persons. In Malaysia, treatment is primarily provided in four established mental health institutions which are the Hospital Permai Johor, Hospital Bahagia Ulu Kinta, Hospital Sentosa, and Hospital Mesra Bukit Padang. This raises a valid question: with only a limited number of specialised institutions, would medical professionals simply certify anyone who pleads insanity?[15] The answer is clearly no. If that were the case, these facilities would be overwhelmed, and public safety would be compromised. In reality, these institutions are reserved for individuals who genuinely require psychiatric care.
Section 23 of the MHA,[16] the patient must be evaluated within 24 hours of admission and thereafter at least once every four weeks throughout the period of detention. During this time, patients participate in structured rehabilitation activities designed to improve their mental and emotional stability. These may include tasks such as baking, cooking, gardening, or vocational training. While these activities may seem simple, they are carefully designed and progressively adjusted to assess behavioural and emotional improvement. Once a patient shows signs of recovery, their case will be reviewed by a Board of Visitors. This board consists of independent members, including a medical officer or psychiatrist who is not attached to the institution, along with other appointed individuals. The Board conducts its own assessment before making any recommendation. Sometimes, even if improvement is shown, the Board often recommends continued treatment before considering reintegration into society. In 2018, out of 20 cases reviewed, only 9 individuals were deemed fit to be reintegrated.[17]
Moreover, even upon release, the accused does not regain complete freedom. They are required to comply with follow-up treatments and medical supervision. Failure to adhere to treatment may result in relapse and potential re-admission. This ensures continued monitoring and public safety.
A notable illustration to sum this up is the case of Andrea Yates,[18] where the court emphasised the importance of treating individuals with severe mental health conditions rather than focusing solely on punishments. Therefore, the idea that insanity operates as a loophole is misplaced. It is not an escape from the law, but a different form of accountability tailored to individuals with genuine mental illness.
EVEN IF THE INSANITY DEFENCE IS COMMONLY USED IT IS SUBJECT TO STRICT LEGAL STANDARDS
The final argument is that even if the insanity defence is commonly used, it is subjected to strict legal standards, making it a highly challenging defence to rely on. A key precedent illustrating this is Public Prosecutor v Shalima Bi.[19] In this case, the accused, the second wife of Mohd Kassim Abu, was alleged to have poured hot oil on the first wife, resulting in her death. The children of the deceased were awakened by her screams and attempted to help, but the accused threatened them with a knife, preventing any assistance. Medical evidence showed that the accused has a long history of mental illness and had undergone treatment. A doctor testified that she had difficulty controlling her actions and emotions.
Through Shalima Bi’s case, the Court of Appeal held that the absence of the motive was significant. The prosecution had failed to establish any clear motive for killing, which weakened their case. In the landmark case of Woolmington v DPP,[20] where it was established that the prosecution bears the burden of proving the accused’s guilt beyond a reasonable doubt, regardless of the defence raised. These principle are in line with maxims such as like actus non facit reum nisi mens sit rea and furiosi nulla voluntas est.
Delving into the standard of burden of proof, while the prosecution must prove its case beyond reasonable doubt, the accused bears the burden of establishing the defence of insanity. This is clearly provided under Section 105 of the Evidence Act (EA),[21] where the accused must prove, on a balance of probabilities, that due to unsoundness of mind, they were incapable of understanding the nature of their act. This involves producing credible evidence, including oral, documentary, and expert (psychiatric) evidence, to rebut the prosecution’s case.
Moving on to the medical evaluation which is also a critical component here. Psychiatric reports are essential in establishing a prima facie case.[22] These reports typically address three key questions: whether the accused suffers from a mental disorder, whether they were of unsound mind at the time of the offence, and whether they are fit to stand trial. Without such evidence, the defence is unlikely to succeed. In Kofri Mustafar v Public Prosecutor,[23] where the accused claimed memory loss but failed to provide medical reports. The court rejected the defence and upheld the conviction. Similarly, in Zulkifli bin Majinjin v Public Prosecutor,[24] the accused merely claimed drug use without supporting medical evidence. The absence of expert testimony led to his conviction.
In short, all of these cases clearly demonstrate that the medical experts and forensic psychiatrics play a crucial role in assisting the court to reach a just decision. Their opinions are admissible under Section 45 EA.[25]
C. CONCLUSION
Every law has potential loopholes. If someone manages to exploit a gap, unfortunately liability may be avoided. However, this is not entirely within the control of lawmakers. What can be done is to ensure that legal standards are strict, clear, and properly enforced. To even strengthen the defence of insanity in Malaysia, the court should establish an independent panel of psychiatrists who are fully neutral and assess the accused strictly based on medical findings. This would reduce bias.
Furthermore, psychiatrists should adopt more open-ended questioning during assessments. This helps them better understand the accused’s awareness of their actions and whether they genuinely lack capacity to recognise the nature of their conduct.[26] Comparatively, jurisdictions such as the United Kingdom consider the accused’s full medical and behavioural history, including prior psychiatric records.[27]
In conclusion, three key points are clear, first, the insanity defence is highly complex and requires strong evidence of mental incapacity, second, even when successful, it leads to confinement in a mental health facility rather than freedom, and third, it is rarely used and subject to strict legal standards, making it difficult to abuse.
Therefore, the insanity defence is not a legal loophole. It is a controlled legal mechanism designed to balance justice, responsibility, and humanity. Individuals suffering from mental illness should be seen as needing assistance and treatment, not merely punishment or stigma.
REFERENCE(S):
All Answers ltd, ‘M’Naghten Rules: Knowledge of Wrong and the Windle Case’ (May 24, 2024, 8 AM) https://www.lawteacher.net/free-law-essays/criminal-law/mnaghten-rule-knowledge-wrong-8377.php?vref=1.
Hari Singh Gond v State of Madhya Pradesh AIR SC 1261 (1965) (India).
Insanity, Oxford English Dictionary (online ed. April 13, 2024, 2.54 PM), https://www.oed.com.
Jannah & Nurul, “Defence of Unsoundness of Mind Under S.84 of Penal Code” pg 23,27,29 (2010).
John Nyumbei v Public Prosecutor 4 MLJ 567 (2012) (Malaysia).
Kofri Mustafar v Public Prosecutor 5 MLJ 123 (2018) (Malaysia).
Nkulukusa, (2013), “The Burden of Proof and The Standard of Proof : Defence of Insanity,” (April 24, 2024, 10.40AM) https://dspace.unza.zm/items/36b37688-ad00-462c-a5f1-80597f37adc8.
Public Prosecutor v Kenneth Lee Fook Mun 1 MLJ 334 (2007) (Malaysia).
Public Prosecutor v Shalima Bi 2 MLJ 789 (2016) (Malaysia).
Resnick, Philip,“Insanity Defence Evaluations : Basic Procedures and Best Practices,” (April 29, 2024, 9.04AM)
Simran, “Insanity : A Loophole for Criminals”, 24,25,26 (2025)
Sinnasamy v Public Prosecutor 3 MLJ 456 (2005) (Malaysia).
The Criminal Procedure Code, Act 593, § 347; § 348(1).
The Evidence Act, 1950, § 45. § 105
The Mental Health Act, 2001, § 23.
The Penal Code, 1950, § 84.
University Malaya, Faculty of Law, “A Review of Standards Used by Courts to Prove Legal Insanity in Malaysia”,( April 12, 2024, 9.04AM https://www.studocu.com/my/document/universiti-malaya/criminal-law/defence-of-insanity/8579479.
Woolmington v DPP AC 462 (1935) (United Kingdom).
Yates v States 171 S.W.3d 215 (2005) (State of Texas).
Zulkifli bin Majinji v Public Prosecutor 2 MLJ 890 (2015) (Malaysia).
[1] Jannah & Nurul, “Defence of Unsoundness of Mind Under S.84 of Penal Code” pg 23,27,29 (2010).
[2] Simran, “Insanity : A Loophole for Criminals”, 24,25,26 (2025).
[3] Insanity, Oxford English Dictionary (online ed. April 13, 2024, 2.54 PM), https://www.oed.com.
[4] The Penal Code, 1950, § 84.
[5] University Malaya, Faculty of Law, “A Review of Standards Used by Courts to Prove Legal Insanity in Malaysia”,( April 12, 2024, 9.04AM https://www.studocu.com/my/document/universiti-malaya/criminal-law/defence-of-insanity/8579479.
[6] John Nyumbei v Public Prosecutor 4 MLJ 567 (2012) (Malaysia).
[7] The Penal Code, 1950, § 84.
[8] Sinnasamy v Public Prosecutor 3 MLJ 456 (2005) (Malaysia).
[9] Public Prosecutor v Kenneth Lee Fook Mun 1 MLJ 334 (2007) (Malaysia).
[10] Resnick, Philip,“Insanity Defence Evaluations : Basic Procedures and Best Practices,” (April 29, 2024, 9.04AM)
https://www.psychiatrictimes.com/view/insanity-defense-evaluations-basic-procedure-and-best-practices.
[11] Hari Singh Gond v State of Madhya Pradesh AIR SC 1261 (1965) (India).
[12] The Criminal Procedure Code, Act 593, § 347.
[13] The Criminal Procedure Code, Act 593, § 348(1).
[14] The Mental Health Act, 2001.
[15] All Answers ltd, ‘M’Naghten Rules: Knowledge of Wrong and the Windle Case’ (May 24, 2024, 8 AM) https://www.lawteacher.net/free-law-essays/criminal-law/mnaghten-rule-knowledge-wrong-8377.php?vref=1.
[16] The Mental Health Act, 2001, § 23.
[17] All Answers ltd, ‘M’Naghten Rules: Knowledge of Wrong and the Windle Case’ (May 24, 2024, 8 AM) https://www.lawteacher.net/free-law-essays/criminal-law/mnaghten-rule-knowledge-wrong-8377.php?vref=1
[18] Yates v States 171 S.W.3d 215 (2005) (State of Texas).
[19] Public Prosecutor v Shalima Bi 2 MLJ 789 (2016) (Malaysia).
[20] Woolmington v DPP AC 462 (1935) (United Kingdom).
[21] The Evidence Act, 1950, § 105.
[22] Nkulukusa, (2013), “The Burden of Proof and The Standard of Proof : Defence of Insanity,” (April 24, 2024, 10.40AM) https://dspace.unza.zm/items/36b37688-ad00-462c-a5f1-80597f37adc8.
[23] Kofri Mustafar v Public Prosecutor 5 MLJ 123 (2018) (Malaysia).
[24] Zulkifli bin Majinji v Public Prosecutor 2 MLJ 890 (2015) (Malaysia).
[25] The Evidence Act, 1950, § 45.
[26] Resnick, Philip,“Insanity Defence Evaluations : Basic Procedures and Best Practices,” (Jan April 29, 2024)
https://www.psychiatrictimes.com/view/insanity-defense-evaluations-basic-procedure-and-best-practices.
[27] University Malaya, Faculty of Law, “A Review of Standards Used by Courts to Prove Legal Insanity in Malaysia”,( April 12, 2024, 9.04AM https://www.studocu.com/my/document/universiti-malaya/criminal-law/defence-of-insanity/8579479.
