The standard of legal insanity, which is complete deprivation of intelligence, is a concept born out of the narrow view that rejects the psychodynamic nature of human psychology. It fails to acknowledge that mental illnesses exist in a spectrum and its all-or-nothing notion of mental illnesses reflects a detachment from established and contemporary concepts of mental health.^[1]

Persons who suffer from mental illnesses are no longer viewed as wild beasts who are absolutely devoid of mental faculties. The diagnosis and studies on mental illnesses and disorders have progressed since. Attitude and views towards mental health have significantly evolved. Tests have been recalibrated and reformulated to better deal with the peculiarity and contours of insanity defense cases-tests whose merits are now recognized by this Court.

We clarify the guidelines laid down in People v. Formigones^[2] and now apply a three-way test: first, insanity must be present at the time of the commission of the crime; second, insanity, which is the primary cause of the criminal act, must be medically proven; and third, the effect of the insanity is the inability to appreciate the nature and quality or wrongfulness of the act.

This Court resolves an appeal from the Decision^[3] of the Court of Appeals affirming Lito Pa a's (Pa a) conviction for the crime of murder.

Pa a was charged with murder under the following Information:

That on or about the 20^th day of March 2005, at about 7:30 o 'clock in the morning at Barangay Masaya, Municipality of Rosario, Province of Batangas, Philippines, and within the jurisdiction of this Honorable Court, the above-named accused, armed with a bolo (gulok) with intent to kill with the qualifying circumstances of treachery and evident premeditation, with a buse of superior strength and without any justifiable cause, did then and there willfully, unlawfully and feloniously attack, assault and hack with the said bolo one Sherwin Macatangay y Lara, suddenly and without warning, thereby int1icting upon the latter incise wounds on his head and neck, which directly caused his death.

Contrary to law.^[4]

Upon arraignment, Pa a pleaded not guilty to the charge. Trial on the merits ensued.^[5]

The prosecution presented the following witnesses: (1) the victim's mother, Thelma Macatangay; (2) Aldwin Andal (Andal); (3) PO3 Andres Mancia (PO3 Mancia); and (4) Municipal Health Officer Dr. Emelita Abacan (Dr. Abacan).^[6]

Based on the collective testimony of its witnesses, the prosecution alleged that on March 20, 2005, Andal left his house at around 7:30 a.m. to fetch Sherwin Macatangay (Macatangay) from the latter's hut. When Andal arrived, he saw Pa a hacking Macatangay with a two-foot long bolo. Macatangay was sleeping on the katre (bed) while he was being hacked. Afraid of what he had just witnessed, Andal immediately ran away and reported the incident to the authorities.^[7]

PO3 Mancia and PO1 Ronilo Balita (PO1 Balita) were dispatched from the Rosario Police Station to proceed to the crime scene.^[8] When they arrived, they saw numerous bystanders in the area. They searched the place and saw Macatangay's lifeless body. While they were conducting their on-site investigation, PO3 Mancia and PO1 Balita found Pa a in a grassy lot 25 to 30 meters away from the crime scene. Pa a was lying on the ground with a bolo in his hand. When Pa a saw the police officers, he attempted to run but he was immediately apprehended. He was then brought to the police station.^[9]

The post-mortem examination conducted by Dr. Abacan revealed that Macatangay sustained four (4) incised wounds on his head and neck, which caused his death.^[10]

After the prosecution rested its case, the defense presented Pa a and his mother, Soledad Pa a (Soledad), as witnesses. Pa a interposed the defense of insanity.

Pa a claimed that he had been mentally ill since 2003 which caused him to do things he was unaware of, suffer sleepless nights, and even attempt to commit suicide twice. In one instance, he jumped from a bridge but did not suffer any injuries. He further claimed that he was mentally ill in November 2004 and January 2005. He claimed that he absolutely had no recollection of what transpired on the day of the alleged incident and that he only regained his mental faculties after his apprehension and incarceration. The quack doctor whom he had previously consulted told him that his mental illness was brought about by depression.^[11]

Soledad corroborated her son's testimony. She testified that her son was having health problems before the alleged incident and was quiet and uneasy most of the time. Soledad knew that her son was not in his right mind because he would answer differently whenever she would talk to him. Due to financial constraints, they were unable to seek professional medical intervention. On the day of the alleged incident, Soledad observed that her son had a blank stare on his face ('nakatulala').^[12]

Moreover, Soledad maintained that his son and the victim, who were close cousins, did not have any misunderstandings. When she visited her son in jail, he was allegedly still unaware of what happened and did not recognize anyone.^[13]

In its Decision,^[14] the Regional Trial Court found Pa a guilty. The dispositive portion of its Decision reads:

For failure to establish by convincing evidence his alleged insanity at the time that accused killed Sherwin Macatangay, the Court renders its judgment of CONVICTION and hereby sentence the accused LITO PA A Y INANDAN to suffer the penalty of Reclusion Perpetua.

Furthermore, the accused LITO PA A Y INANDAN is directed to pay the heirs of Sherwin Macatangay y Lara the amount of Php 50,000.00 as death indemnity.

SO ORDERED.^[15]

The Regional Trial Court found the evidence presented by the defense insufficient to establish Pa a's claim of insanity. The Regional Trial Court did not consider Pa a and his mother as competent witnesses to testify on Pa a's state of mind. Assuming their testimonies were given weight, it held that there was no proof that Pa a was completely deprived of intelligence when the crime was committed.^[16]

Pa a appealed the Decision of the Regional Trial Court. In his Appellant's Brief,^[17] Pa a argued that expert testimony is not indispensable to prove his insanity as this may be established by the testimony of one who is intimately acquainted with him. Pa a believes that his mother is the best witness to testify on his mental condition having observed his day-to-day behavior.^[18]

Further, Pa a argued that he had no ill motive toward the victim and there was no misunderstanding between them. Moreover, the totality of the circumstances suggests that he was unaware of what he had done: first, he killed the victim in broad daylight; second, he was found around 25 to 30 meters away from the crime scene after the incident; and lastly, he has shown no remorse.^[19]

On the other hand, the People of the Philippines, through the Office of the Solicitor General, argued in its Brief^[20] that Pa a's guilt has been proven beyond reasonable doubt. It stated that the act of killing a sleeping victim is considered treacherous. Thus, the trial court did not err in rendering a judgment of conviction.^[21]

As regards Pa a's defense of insanity, the Office of the Solicitor General argued that legal insanity requires that the accused must be "deprived of reason and act without the least discernment[.]"^[22] The Office of the Solicitor General believes that the evidence presented by the defense showed that Pa a only exhibited unusual behavior.^[23]

The Court of Appeals affirmed Pa a's conviction in its March 13, 2014 Decision.^[24] Thus:

WHEREFORE, the instant appeal is DISMISSED and the Decision dated January 24, 2012 of the Regional Trial Court of Rosario, Batangas, Branch 87, in Criminal Case No. R05-065 is AFFIRMED IN TOTO.

SO ORDERED.^[25]

The appellate court agreed with the Regional Trial Court that Pa a and his mother were not competent witnesses to testify on Pa a's alleged insanity.^[26] Moreover, it found no clear evidence that would establish Pa a's insanity immediately before or at the time he killed the victim. It held that the manifestations of Pa a's alleged mental illness are insufficient to prove legal insanity, which requires complete deprivation of intelligence.^[27]

In affirming the finding of guilt, the Court of Appeals found that the prosecution proved all the elements of murder. It held that the number of stab wounds sustained by the victim indicated Pa a's intent to kill. The killing was also attended with treachery as it was done while the victim was sleeping.^[28]

Pa a filed his Notice of Appeal^[29] which was given due course by the Court of Appeals.^[30] The records were then elevated to this Court.^[31]

In a Resolution,^[32] this Court noted the records forwarded by the Court of Appeals and required the parties to submit their respective supplemental briefs. Both parties manifested that they would no longer file their supplemental briefs.^[33]

The issue for this Court's resolution is whether or not accused-appellant Lito Pa a y Inandan can claim exemption from criminal liability based on the defense of insanity.

I

One of the basic moral assumptions in criminal law is that all persons are "naturally endowed with the faculties of understanding and free will."^[34] When a person is charged of a crime, the act is deemed to have been committed with "deliberate intent, that is, with freedom, intelligence[,] and malice."^[35]

The presumption in favor of sanity is based on practical considerations. As explained by this Court in People v. Aquino:^[36]

The basis for the presumption of sanity is well explained by the United States Supreme Court in the leading case of Davis vs. United States, in this wise: "If that presumption were not indulged, the government would always be under the necessity of adducing affirmative evidence of the sanity of an accused. But a requirement of that character would seriously delay and embarrass the enforcement of the laws against crime and in most cases be unnecessary. Consequently, the law presumes that everyone charged with crime is sane and thus, supplies in the first instance the required proof of capacity to commit crime."^[37] (Citation omitted)

Since the law presumes all persons to be of sound mind, insanity is the exception rather than the general rule.^[38] It is a defense in the nature of confession and avoidance.^[39] In claiming insanity, an accused admits the commission of the criminal act but seeks exemption from criminal liability due to lack of voluntariness or intelligence.^[40]

Under Article 12(1) of the Revised Penal Code:

CHAPTER TWO

Justifying Circumstances and Circumstances which Exempt from Criminal Liability

ARTICLE 12. Circumstances Which Exempt from Criminal Liability. - The following are exempt from criminal liability:

1. An imbecile or an insane person, unless the latter has acted during a lucid interval.

When the imbecile or an insane person has committed an act which the law defines as a felony (delito), the court shall order his confinement in one of the hospitals or asylums established for persons thus atl1icted, which he shall not be permitted to leave without first obtaining the permission of the same court.^[41]

This Court defines insanity as:

a manifestation in language or conduct of disease or defect of the brain, or a more or less permanently diseased or disordered condition of the mentality, functional or organic, and characterized by perversion, inhibition, or disordered function of the sensory or of the intellective faculties, or by impaired or disordered volition.^[42]

An insane person "has an unsound mind or suffers from a mental disorder,"^[43] but this Court admits that an insane person may have lucid intervals during which they may be held liable for criminal acts.^[44]

Previously, the inquiry in insanity defense cases had no clear parameters. It merely posed the question of whether the accused was insane at the time they committed the offense.^[45] There had been no defined standards as to what distinctly constituted insanity until 1950 when this Court, in People v. Formigones,^[46] adopted the complete deprivation of intelligence or will test.

In Formigones, the accused was charged with parricide for stabbing his wife. He interposed the defense of insanity under Article 12(1) of the Revised Penal Code, alleging that during trial, guards of the provincial jail testified that the accused exhibited strange behavior and behaved like an insane person during his incarceration.^[47]

There, this Court rejected the defense of insanity. Citing decisions of the Supreme Court of Spain, it held that for an accused to be regarded as an imbecile within the contemplation of the Revised Penal Code, there must be complete deprivation of reason, discernment, or freedom of the will at the time of the commission of the crime.^[48] Thus:

In order that a person could be regarded as an imbecile within the meaning of article 12 of the Revised Penal Code so as to be exempt from criminal liability, he must be deprived completely of reason or discernment and freedom of the will at the time of committing the crime. The provisions of article 12 of the Revised Penal Code are copied from and based on paragraph I, article 8, of the old Penal Code of Spain. Consequently, the decisions of the Supreme Court of Spain interpreting and applying said provisions are pertinent and applicable. We quote Judge Guillermo Guevara on his Commentaries on the Revised Penal Code, 4th Edition, pages 42 to 43:

"The Supreme Court of Spain held that in order that this exempting circumstance may be taken into account, it is necessary that there be a complete deprivation of intelligence in committing the act, that is, that the accused be deprived of reason; that there be no responsibility for his own acts; that he acts without the least discernment; that there be a complete absence of the power to discern, or that there be a total deprivation of freedom of the will. For this reason, it was held that the imbecility or insanity at the time of the commission of the act should absolutely deprive a person of intelligence or freedom of will, because mere abnormality of his mental faculties does not exclude imputability.

"The Supreme Court of Spain likewise held that deaf-muteness cannot be equalled to imbecility or insanity.

"The allegation of insanity or imbecility must be clearly proved. Without positive evidence that the defendant had previously lost his reason or was demented, a few moments prior to or during the perpetration of the crime, it will be presumed that he was in a normal condition. Acts penalized by law are always reputed to be voluntary, and it is improper to conclude that a person acted unconsciously, in order to relieve him from liability, on the basis of his mental condition, unless his insanity and absence of will are proved."^[49] (Citations omitted)

The formulation in Formigones gave rise to two distinguishable tests in determining the existence of legal insanity: (1) the test of cognition; and (2) the test of volition.^[50] The test of cognition requires a "complete deprivation of intelligence in committing the [criminal] act" while the test of volition requires a "total deprivation of freedom of the will."^[51] Despite the existence of these standards by which legal insanity can be measured, a review of jurisprudence shows more reliance on the test of cognition.^[52]

This observation was echoed in People v. Rafanan, Jr.:^[53]

A linguistic or grammatical analysis of those standards suggests that Formigones established two (2) distinguishable tests (a) the test of cognition - "complete deprivation of intelligence in committing the [criminal] act," and (b) the test of volition - "or that there be a total deprivation of freedom of the will." But our caselaw shows common reliance on the test of cognition, rather than on a test relating to "freedom of the will;" examination of our caselaw has failed to turn up any case where this Court has exempted an accused on the sole ground that he was totally deprived of "freedom of the will," i.e., without an accompanying "complete deprivation of intelligence." This is perhaps to be expected since a person's volition naturally reaches out only towards that which is presented as desirable by his intelligence, whether that intelligence be diseased or healthy. In any case, where the accused failed to show complete impairment or loss of intelligence, the Court has recognized at most a mitigating, not an exempting, circumstance in accord with Article 13(9) of the Revised Penal Code: "Such illness of the offender as would diminish the exercise of the will-power of the offender without however depriving him of the consciousness of his acts."^[54] (Citation omitted)

As expounded in People v. Haloc:^[55]

The defense of insanity rests on the test of cognition on the part of the accused. Insanity, to be exempting, requires the complete deprivation of intelligence, not only of the will, in committing the criminal act. Mere abnormality of the mental faculties will not exclude imputability. The accused must be so insane as to be incapable of entertaining a criminal intent. He must be deprived of reason, and must be shown to have acted without the least discernment because there is a complete absence of the power to discern or a total deprivation of freedom of the will.^[56] (Citations omitted)

Since Formigones, the standard on insanity defense cases has remained the same and a low rate of acceptance of insanity persisted in our jurisdiction. The test is stringent because it requires complete deprivation of reason and intelligence. Any indication of cognition or reason before, during, or after the commission of the crime leads to a rejection of the defense. Rarely does complete deprivation of cognition get proven in court. In fact, a survey of jurisprudence shows that only two cases passed this strict standard.

In the 1996 case of People v. Austria,^[57] it was alleged that the accused suffered from paranoid type schizophrenia, which is characterized by "unpredictable assaultiveness" and "violent and destructive behavior," among others. According to psychiatric evaluation, his auditory hallucinations recurred and he was experiencing a relapse. A week later, he allegedly had the sudden urge to have sexual intercourse with the victim after being intoxicated by 10 bottles of beer. He then went to the victim's house and when she refused to have intercourse with him, he claimed to hear the devil ordering him to stab the victim and her children. During trial, the psychiatrist testified that the accused had previously been confined and that his mental condition cannot be cured by medication.^[58]

In acquitting the accused, this Court held that there was sufficient evidence showing that he was insane at the time he committed the crime. The Court gave weight to the fact of his previous confinement, his erratic behavior prior to the incident, and the psychiatrist's testimony which confirmed that he was having a relapse, completely depriving him of reason at the time of the incident.^[59]

In the more recent case of Verdadero v. People,^[60] decided in 2016, this Court acquitted the accused based on the testimony of his psychiatrist, who categorically claimed that the accused was diagnosed with schizophrenia. The psychiatrist further testified that the accused had several relapses in the past and, again, at the time of the stabbing incident. This was consistent with the testimony of the accused's neighbor who narrated that the accused was of unsound mind, noting that on the day of the incident he had reddish eyes and appeared drunk.^[61]

In Verdadero, while there was no direct evidence showing the accused's mental state at the precise moment of the incident, this Court held that insanity was sufficiently proven by the circumstances immediately before and after the incident. Considering the expert testimony which is corroborated by another witness, this Court ruled that there was sufficient evidence showing that the accused was deprived of intelligence at the time of the commission of the offense.^[62]

Save for Austria and Verdadero, schizophrenia, which has often been cited to support a claim of insanity, has usually never passed the test of cognition in Formigones. This is because schizophrenia is not automatically accompanied by loss of intelligence.^[63] In Rafanan, Jr.:

Schizophrenia pleaded by appellant has been described as a chronic mental disorder characterized by inability to distinguish between fantasy and reality, and often accompanied by hallucinations and delusions. Formerly called dementia praecox, it is said to be the most common form of psychosis and usually develops between ages 15 and 30....

....

In previous cases where schizophrenia was interposed as an exempting circumstance, it has mostly been rejected by the Court. In each of these cases, the evidence presented tended to show that if there was impairment of the mental faculties, such impairment was not so complete as to deprive the accused of intelligence or the consciousness of his acts.^[64] (Emphasis in the original, citations omitted)

Complete deprivation of intelligence has been equated to "defect of the understanding"^[65] such that the accused must have "no full and clear understanding of the nature and consequences of [their] acts."^[66] Deprivation of intelligence, however, is not a symptom of every mental illness. In People v. Opuran:^[67]

Insanity is evinced by a deranged and perverted condition of the mental faculties which is manifested in language and conduct. However, not every aberration of the mind or mental deficiency constitutes insanity. As consistently held by us, "A man may act crazy, but it does not necessarily and conclusively prove that he is legally so." Thus, we had previously decreed as insufficient or inconclusive proof of insanity certain strange behavior, such as, taking 120 cubic centimeters of cough syrup and consuming three sticks of marijuana before raping the victim; slurping the victim's blood and attempting to commit suicide after stabbing him; crying, swimming in the river with clothes on, and jumping off a jeepney.^[68] (Citations omitted)

Feeblemindedness has also been rejected by this Court as sufficient basis to support a claim of insanity.^[69] In Formigones, the accused was not deemed insane as he was not completely deprived of reason at the time he committed the offense and could still distinguish right from wrong. Even his past conduct did not indicate that he was mentally ill:

He regularly and dutifully cultivated his farm, raised five children, and supported his family and even maintained in school his children of school age, with the fruits of his work. Occasionally, as a side line he made copra. And a man who could feel the pangs of jealousy and take violent measures to the extent of killing his wife whom he suspected of being unfaithful to him, in the belief that in doing so he was vindicating his honor, could hardly be regarded as an imbecile. Whether or not his suspicions were justified, is of little or no import. The fact is that he believed her faithless.^[70]

The complete deprivation of intelligence or will test originated from the old English concept of "wild beast test," which likens defendants to wild beasts due to their "complete lack of understanding" of their actions.^[71] English jurisprudence held that to be insane, an accused "must be totally deprived of his understanding and memory so as not to know what he is doing, no more than an infant, brute or a wild beast."^[72] This test placed more emphasis on the accused's cognitive capacity rather than impulses, and raised the criteria which effectively reduced the rate of acquittal in insanity defense cases.^[73]

Several other tests were developed in various jurisdictions. The most prominent of these tests is the M'Naghten Rule.

Under the M'Naghten Rule, the defense of insanity would only prosper if there is sufficient evidence that at the time the offense was committed, the accused was unaware of "the nature and quality of the act he was doing, or, if he did know it, that he did not know he was doing what was wrong."^[74]

Like the wild beast test, the English Colll1 also formulated the M'Naghten Rule. In that case, accused Daniel M'Naghten shot Edward Drummond dead, mistaking him for UK Prime Minister Robert Peel. M'Naghten was proven to have been suffering from morbid delusions, convincing himself that the Prime Minister will kill him. The Court acquitted him on the ground of insanity and gave credence to evidence which pointed out that due to his delusions, he was unable to distinguish between right and wrong and was incapable of controlling his conduct in connection with the delusion.^[75]

The M'Naughten Rule was promptly adopted by most United States state courts.^[76] However, the test was criticized for its ambiguity, raising debates whether the term wrong qualifies as moral or legal wrong.^[77] Moreover, it was disapproved for its confined focus on cognitive impairment, which totally disregards an accused's ability to control their behavior.^[78]

As a response to the criticism towards the M'Naghten Rule, the irresistible impulse test was formulated in the United States.^[79] This test focuses on a person's volition and the causation between the mental illness and the resulting conduct, removing the element of free will in the commission of the crime.^[80]

The irresistible impulse test provides that even if the accused was aware of the nature and quality of the criminal act, they would nevertheless be exempted from criminal liability if it is proven that the accused "has been deprived of or lost the power of his will[.]"^[81] The accused must have either lost control of their conduct or failed to resist the impulse to commit the crime.^[82] However, this test has been criticized because it is too restrictive^[83] and because an irresistible attack can be easily feigned.^[84]

The third test, known as the Durham Product Test, puts more emphasis on the acts produced by a person who is suffering from a mental disease. Proponents of this test postulate that all acts resulting from a mental disease are not criminal. An accused may be exonerated from criminal liability if his or her "unlawful act was the product of mental disease or defect." Critics, however, consider the application of this rule too broad.^[85] The vagueness of the terms "mental disease or defect" and "product" resulted to confusion and circuitous disputes on legal and medical jargons.^[86]

The fourth test is the substantial capacity test, otherwise known as the American Law Institute (ALI) Standard. It is a species of the M'Naghten Rule and the irresistible impulse test.

The substantial capacity test provides that an accused suffering from a mental disease or defect is not criminally liable if they "[lack] substantial capacity to appreciate the criminality of [their] act or to conform [their] conduct to the requirements of the law."^[87]

However, critics questioned the substantial capacity test's volitional prong (i.e. to conform the conduct to the law), which was seen as a step back from M'Naghten Rule's volition requirement.^[88] As a result, a new test was recommended and later adopted by the United States in the Insanity Defense Reform Act of 1984.^[89]

Under the Insanity Defense Reform Act, a defendant is not criminally liable if "at the time of the commission of the acts constituting the offense, the defendant, as a result of a severe mental disease or defect, was unable to appreciate the nature and quality of the wrongfulness of his acts."^[90] Thus, the law eliminated the volition prong of the insanity defense.^[91]

The Insanity Defense Reform Act introduced three changes: first, it restricted the standard of insanity in M'Naghten Rule; second, it shifted the burden of proof to the defendant; and third, it prohibited experts from testifying with respect to the ultimate legal issue of whether the defendant was insane at the time of the commission of the crime.^[92]

Several jurisdictions have adopted standards similar to the formulation in the M'Naghten Rule and Insanity Defense Reform Act.

In Canada, the insanity defense may prosper if the accused committed the crime "while suffering from mental disorder that rendered [him or her] incapable of appreciating the nature and the quality of an act or omission or of knowing that it was wrong."^[93] Similarly, the Criminal Code of Germany exempts an accused from criminal responsibility "if at the time of the act, because of a psychotic, or similar serious mental disorder, or because of a profound interruption of consciousness or because of feeblemindedness or any other type of serious mental abnormality, he is incapable of understanding the wrongfulness of his conduct or of action in accordance with his understanding."^[94] In Spain, an accused will be exempt from criminal responsibility if "because of mental disease or defect he was not able to comprehend the illegality of his act or conform his conduct to the mandates of the law."^[95]

Other jurisdictions likewise exempt insane persons from criminal responsibility if the accused, as a result of the mental illness, was unable to recognize or understand the wrongfulness or consequences of the act.^[96]

In our jurisdiction, the more stringent test formed in Formigones remained the standard in determining insanity.^[97] Nevertheless, tests other than the formulation in Formigones are suppletorily used by this Court to determine whether there was complete deprivation of intelligence in the commission of the crime.

In a number of cases, this Court resolved insanity cases by ascertaining whether the accused was aware of their acts' wrongfulness. For instance, immediate surrender to the authorities,^[98] escaping arrest,^[99] display of remorse,^[100] and threatening the victim to avoid getting caught^[101] have been considered proof that the accused knew the nature and culpability of their acts.^[102]

In People v. Ambal,^[103] using the Formigones Test, this Court concluded that the presumption of sanity was not overthrown by evidence, and that the accused was "not completely bereft of reason or discernment and freedom of will" when he killed his wife. This Court cited how the accused knew and understood the wrongfulness and consequences of his conduct when he thought of surrendering to the authorities.^[104]

Similarly, in People v. Rafanan, Jr.,^[105] this Court ruled that a showing that the accused understood the wrongfulness of his act determines that he was not completely deprived of intelligence. That the accused threatening the victim with death indicates that the accused was aware of the reprehensibility of his act.^[106]

III

Under our current rule, complete deprivation of intelligence or reason at the time of the commission of the crime is an assertion which must be proven beyond reasonable doubt.

Insanity relates to a person's state of mind. However, a person's motivations, thoughts, and emotions are only manifested through overt acts.^[107] Courts, therefore, can only consider evidence relating to the behavioral patterns of the accused to determine whether they are legally insane. In People v. Madarang:^[108]

The issue of insanity is a question of fact for insanity is a condition of the mind, not susceptible of the usual means of proof. As no man can know what is going on in the mind of another, the state or condition of a person's mind can only be measured and judged by his behavior.^[109]

The complete deprivation of intelligence must be manifested at the time "preceding the act under prosecution or to the very moment of its execution."^[110] Thus, courts admit evidence or proof of insanity which relate to the time immediately before, during, or after the commission of the offense.^[111] In People v. Dungo:^[112]

Evidence of insanity must have reference to the mental condition of the person whose sanity is in issue, at the very time of doing the act which is the subject of inquiry. However, it is permissible to receive evidence of his mental condition for a reasonable period both before and after the time of the act in question.^[113]

Because our current rule requires complete deprivation of intelligence, the slightest sign of reason before, during, or after the commission of the crime instantly overthrows the insanity defense.

This is despite the wording of our penal law and recognition in our jurisprudence that an insane person's mental condition is not static and that they may experience lucid intervals from time to time.^[114] This is especially critical in our jurisdiction where insanity defense is mostly claimed based on mental disorders with active-phase symptoms such as schizophrenia.^[115]

Further, complete deprivation of intelligence is a concept born of a medieval view of mental illnesses which rejects the psychodynamic nature of human psychology.^[116] It fails to acknowledge that mental illnesses exist in a spectrum and the all-or-nothing notion of mental illnesses reflects our legal system's detachment from established and contemporary concepts of mental health.^[117]

Persons who suffer from mental illnesses and disorders are no longer viewed as wild beasts who are absolutely devoid of mental faculties. The diagnosis and studies on mental illnesses and disorders have progressed since. Attitude and views toward mental health have significantly evolved. Tests have been recalibrated and reformulated to better deal with the peculiarity and contours of insanity defense cases-tests whose merits are now recognized by this Court.

IV

This Court in People v. Bascos^[118] began the query on the appropriate quantum of evidence for insanity defense to prosper. Bascos observed the prevailing conflict of authority in fixing the quantum of evidence required from the defense in insanity cases. t held that whatever the quantum is, it must be in harmony with two fundamental and basic criminal law propositions, specifically: (1) that the prosecution bears the burden to establish the commission of the crime with proof beyond reasonable doubt; and (2) that there is a presumption in favor of sanity.^[119]

However, Bascos did not categorically state the quantum of evidence required to prove insanity. It discussed:

The responsibility of the insane for criminal action has been the subject of discussion for centuries. Some criminologists, psychiatrists, and lawyers have contended with much earnestness that the defense of insanity should be done away with completely. Indeed, in at least one State of the American Union, that of the State of Washington, the Legislature has passed a statute abolishing insanity as a defense.

In the Philippines, among the persons who are exempted from criminal liability by our Penal Code, is the following:

"An imbecile or lunatic, unless the latter has acted during a lucid interval.

"When the imbecile or lunatic has committed an act which the law defines as a grave felony, the court shall order his confinement in one of the asylums established for persons thus afflicted, which he shall not be permitted to leave without first obtaining the permission of the same court." (Art. 8-1)

Article 100 of the Penal Code applies when the convict shall become insane or an imbecile after final sentence has been pronounced.

In reference to the burden of proof of insanity in criminal cases, where the defense of insanity is interposed, a conflict of authority exists. At least, all the authorities are in harmony with reference to two fundamental propositions: First, that the burden is on the prosecution to prove beyond a reasonable doubt the defendant committed the crime; and secondly, that the law presumes every man to be sane. The conflict in the decisions arises by reason of the fact that the courts differ in their opinion as to how much evidence is necessary to overthrow this original presumption of sanity, and as to what quantum of evidence is sufficient to enable the court to say that the burden of proving the crime beyond a reasonable doubt has been sufficiently borne. (14 R. C L., 624.)

The rather strict doctrine "that when a defendant in a criminal case interposes the defense of mental incapacity, the burden of establishing that fact rests upon him," has been adopted in a series of decisions by this court. (U. S. vs. Martinez [1916], 34 Phil., 305; U. S. vs. Hontiveros Carmona [1910], 18 Phil., 62.) The trial judge construed this to mean that the defense must prove that the accused was insane at the very moment the crime was committed.^[120]

People v. Bonoan^[121] provided a more refined discussion on the matter. Bonoan examined three different theories in other jurisdictions. One theory posits that insanity must be proven beyond reasonable doubt, while another suggests that only a preponderance of evidence is required. A more liberal view considers a person's sanity as an essential element of a crime. As such, the prosecution must establish an accused's sanity beyond reasonable doubt.^[122]

Bonoan leaned towards the first and stricter view, requiring proof beyond reasonable doubt to show insanity:

On the question of insanity as a defense in criminal cases, and the incidental corollaries as to the legal presumption and the kind and quantum of evidence required, theories abound and authorities are in sharp conflict. Stated generally, courts in the United States proceed upon three different theories. The first view is that insanity as a defense in a confession and avoidance and as such must be proved beyond a reasonable doubt. When the commission of a crime is established, and the defense of insanity is not made out beyond a reasonable doubt, conviction follows. In other words, proof of insanity at the time of committing the criminal act should be clear and satisfactory in order to acquit the accused on the ground of insanity. The second view is that an affirmative verdict of insanity is to be governed by a preponderance of evidence, and in this view, insanity is not to be established beyond a reasonable doubt. According to Wharton in his "Criminal Evidence", this is the rule in England, and in Alabama, Arkansas, California, Georgia, Idaho, Iowa, Kentucky, Louisiana, Maine, Massachusetts, Michigan, Minnesota, Missouri, Nevada, New Jersey, New York, North Carolina, Ohio, Pennsylvania, South Carolina, Texas, Virginia and West Virginia. The third view is that the prosecution must prove sanity beyond a reasonable doubt. This liberal view is premised on the proposition that while it is true that the presumption of sanity exists at the outset, the prosecution affirms every essential ingredients of the crime charged, and hence affirms sanity as one of such essential ingredients, and that a fortiori where the accused introduces evidence to prove insanity it becomes the duty of the State to prove the sanity of the accused beyond a reasonable doubt.

In the Philippines, we have approximated the first and stricter view. The burden, to be sure, is on the prosecution to prove beyond a reasonable doubt that the defendant committed the crime, but sanity is presumed, and "... when a defendant in a criminal case interposes the defense of mental incapacity, the burden of establishing that fact rests upon him...." We affirm and reiterate this doctrine.^[123] (Emphasis supplied, citations omitted)

The subsequent case of Dungo is more straightforward:

Generally, in criminal cases, every doubt is resolved in favor of the accused. However, in the defense of insanity, doubt as to the fact of insanity should be resolved in favor of sanity. The burden of proving the affirmative allegation of insanity rests on the defense. Thus:

"In considering the plea of insanity as a defense in a prosecution for crime, the starting premise is that the law presumes all persons to be of sound mind. (Art. 800, Civil Code; U.S. v. Martinez, 34 Phil. 305) Otherwise stated, the law presumes all acts to be voluntary, and that it is improper to presume that acts were done unconsciously (People v. Cruz, 109 Phil. 288) ... Whoever, therefore, invokes insanity as a defense has the burden of proving its existence. (U.S. v. Zamora, 52 Phil. 218)"

The quantum of evidence required to overthrow the presumption of sanity is proof beyond reasonable doubt. Insanity is a defense in a confession and avoidance, and as such must be proved beyond reasonable doubt. Insanity must he clearly and satisfactorily proved in order to acquit an accused on the ground of insanity. Appellant has not successfully discharged the burden of overcoming the presumption that he committed the crime as charged freely, knowingly, and intelligently.^[124] (Emphasis supplied)

This threshold was applied in later cases.^[125] Inevitably, this made proving insanity more rigorous.

However, while there were cases that required proof beyond reasonable doubt, this Court, in several instances, digressed and only demanded clear and convincing evidence to prove insanity.^[126] In People v. Austria:

In order to ascertain a person's mental condition at the time of the act, it is permissible to receive evidence of his mental condition during a reasonable period before and after. Direct testimony is not required nor are specific acts of disagreement essential to establish insanity as a defense. A person's mind can only be plumbed or fathomed by external acts. Thereby his thoughts, motives and emotions may be evaluated to determine whether his external acts conform to those of people of sound mind. To prove insanity, clear and convincing circumstantial evidence would suffice.

Under present-day American jurisprudence, the states have a variety of rules regarding who hears the burden of proof in insanity defense cases. Many states and the federal government have placed the burden on the defendant to prove legal insanity by a preponderance of evidence. This is now the majority rule.^[127] (Emphasis supplied, citations omitted)

Similarly, in People v. Tibon:^[128]

While Art. 12 (1) of the Revised Penal Code provides that an imbecile or insane person is exempt from criminal liability, unless that person has acted during a lucid interval, the presumption, under Art. 800 of the Civil Code, is that every human is sane. Anyone who pleads the exempting circumstance of insanity bears the burden of proving it with clear and convincing evidence. It is in the nature of confession and avoidance. An accused invoking insanity admits to have committed the crime but claims that he or she is not guilty because of insanity.^[129] (Emphasis supplied, citations omitted)

The rule must be clarified and rationalized.

An accused interposing the insanity defense admits the commission of the crime which would otherwise engender criminal liability. However, the accused pleas for acquittal due to lack of freedom, intelligence, or malice. In doing so, the defense must prove insanity. However, the shift of burden from the prosecution to defense does not necessarily mean shifting the same quantum of evidence because the allegation sought to be proven are different.

Verily, insanity is not an element of the crime that should be demonstrated with proof beyond reasonable doubt. The defense only bears the burden of disputing the presumption of sanity. Ultimately, the defense must proffer evidence of insanity sufficient to overcome the presumption. This quantum of evidence is not necessarily proof beyond reasonable doubt.

Moreover, proof of defense, mitigation, excuse, or justification in criminal cases need not be proven beyond reasonable doubt.^[130]

In criminal cases involving pleas in the nature of confession and avoidance, clear and convincing evidence is sufficient to acquit the accused. For instance, defendants interposing self-defense are only required to demonstrate self-defense by clear and convincing evidence.^[131] In cases where the justifying circumstance of defense of strangers is invoked, this Court likewise only requires proof by clear and convincing evidence.^[132] The same quantum of evidence applies to cases where the defense of state of necessity is invoked.^[133] Likewise, proof of other exempting circumstances only requires clear and convincing evidence.^[134]

The disparity in the quantum of evidence applied in insanity defenses vis-a-vis other defenses of avoidance and confession does not support any clear judicial policy. It simply imposes a standard more stringent on defendants who are not in full control of their faculties. As we remarked in Verdadero:

The expectations of a person possessed with full control of his faculties differ from one who is totally deprived thereof and is unable to exercise sufficient restraint on his. Thus, it is but reasonable that the actions made by the latter be measured under a lesser stringent standard than that imposed on those who have complete dominion over their mind, body and spirit.^[135]

Therefore, the quantum of evidence in proving the accused's insanity should no longer be proof beyond reasonable doubt, but clear and convincing evidence.

Jurisprudence is witness to the strong suspicion against the insanity defense, with cases remarking that the State must zealously guard against those who feign mental illness to avoid punishment.^[136] This suspicion may be attributed to the perceived invisibility of mental illnesses^[137] and mistrust of diagnoses.^[138]

However, one of the main policy rationales of the insanity defense is the assurance that mentally-ill persons who have violent tendencies be released only when they no longer pose threat to society. Acquittal by reason of insanity puts a restraint on mentally-ill defendants by sending them to rehabilitative facilities for proper psychiatric care. By placing an unreasonably high bar for acceptance of insanity defenses, this policy is defeated because the accused's subsequent release on parole not only poses a threat to society, but also robs them of their needed medical treatment.^[139]

Clarifying guidelines with respect to the legal insanity standard and the quantum of evidence requirement is apt to enable courts to effectively determine which defendants are indeed in need of appropriate psychiatric treatment.

V

Insanity, as an exempting circumstance, must be shown medically, unless there are extraordinary circumstances and there is no other evidence available. Our procedural rules allow ordinary witnesses to testify on the "mental sanity of a person with whom [they are] sufficiently acquainted,"^[140] but reports and evaluation from medical experts have greater evidentiary value in determining an accused's mental state.^[141] The nature and degree of an accused's mental illness can be best identified by medical experts equipped with specialized knowledge to diagnose a person's mental health.^[142]

For instance, People v. Puno^[143] rejected the insanity defense after the Court considered the testimonies of three psychiatrists who testified that accused acted with discernment. Two of them declared that the accused was already an outpatient who is aware of what he is doing and that he can adapt to society even though he was afflicted with schizophrenic reaction. Another psychiatrist noted that the accused was not suffering from delusion and that he could distinguish right from wrong.

In Austria, as discussed earlier, this Court took into account the testimony of a medical expert who stated that the accused was having relapse. In acquitting the accused:

The Court is convinced that the testimonial and documentary evidence marshalled in this case by acknowledged medical experts have sufficiently established the fact that appellant was legally insane at the time he committed the crimes. His previous confinements, as early as 1972, his erratic behavior before the assaults and Dr. Della's testimony that he was having a relapse all point to a man deprived of complete freedom of will or a lack of reason and discernment that should thus exempt him from criminal liability.^[144]

Nevertheless, a diagnosis of mental illness does not instantly resolve a legal question. A finding based on the Diagnostic and Statistical Manual of Mental Disorders 5 (DSM-5), a widely-accepted manual of mental disorders, does not necessarily evince a finding of legal insanity.^[145] For instance, pedophilic disorder is defined by DSM-5 but it is not recognized in our jurisdiction as basis for legal insanity.^[146] Hence, evidence from experts and studies can inform courts of the accused's "cognitive impairment, perceptual problems, behavioral limitations, communication difficulties, and sensory dysfunction."^[147] These factors may aid the courts to understand the accused's decisional and cognitive capabilities.^[148]

This Court realizes the difficulty and additional burden on the accused to seek psychiatric diagnosis. Therefore, judges must be given leeway to order the mental examination of the accused either through discovery procedures or as an incident of trial.

The conduct of mental examination is imperative not only to aid the courts but to determine the accused's mental fitness to participate in trial. This is crucial to accord due process to the accused. In People v. Estrada:^[149]

To put a legally incompetent person on trial or to convict and sentence him is a violation of the constitutional rights to a fair trial and due process of law; and this has several reasons underlying it. For one, the accuracy of the proceedings may not be assured, as an incompetent defendant who cannot comprehend the proceedings may not appreciate what information is relevant to the proof of his innocence. Moreover, he is not in a position to exercise many of the rights afforded a defendant in a criminal case, e.g., the right to effectively consult with counsel, the right to testify in his own behalf, and the right to confront opposing witnesses, which rights are safeguards for the accuracy of the trial result. Second, the fairness of the proceedings may be questioned, as there are certain basic decisions in the course of a criminal proceeding which a defendant is expected to make for himself, and one of these is his plea. Third, the dignity of the proceedings may be disrupted, for an incompetent defendant is likely to conduct himself in the courtroom in a manner which may destroy the decorum of the court. Even if the defendant remains passive, his lack of comprehension fundamentally impairs the functioning of the trial process. A criminal proceeding is essentially an adversarial proceeding. If the defendant is not a conscious and intelligent participant, the adjudication loses its character as a reasoned interaction between an individual and his community and becomes an invective against an insensible object. Fourth, it is important that the defendant knows why he is being punished, a comprehension which is greatly dependent upon his understanding of what occurs at trial. An incompetent defendant may not realize the moral reprehensibility of his conduct. The societal goal of institutionalized retribution may be frustrated when the force of the state is brought to bear against one who cannot comprehend its significance.^[150] (Citations omitted)

While the conduct of mental examination rests upon the discretion of the trial court, this Court may remand the case and order an examination when there are overwhelming indications that the accused is not in the proper state of mind.^[151] Among the factors that may be considered is "evidence of the defendant's irrational behavior, history of mental illness or behavioral abnormalities, previous confinement for mental disturbance, demeanor of the defendant, and psychiatric or even lay testimony bearing on the issue of competency in a particular case."^[152]

In Estrada, this Court ordered the accused's mental examination after finding that he was deprived of fair trial. In that case, the trial court denied the motions of the defense to suspend the arraignment due to the accused's inability to intelligently enter a plea and to place the accused in an institution. It also ignored the jail warden's request to allow the accused's confinement due to his unusual behavior. Moreover, the defense waived the accused's right to testify due to his mental illness.^[153]

Despite these indications, the trial court found that the accused was competent to stand trial because he answered the judge's questions. This Court held that this is not a sufficient finding of the accused's mental capacity and, considering the circumstances of the case, the trial court should have ordered the examination to determine the accused's competency to stand trial.^[154] Underscoring the importance of medical diagnoses, this Court held:

The human mind is an entity, and understanding it is not purely an intellectual process but depends to a large degree upon emotional and psychological appreciation. Thus, an intelligent determination of an accused's capacity for rational understanding ought to rest on a deeper and more comprehensive diagnosis of his mental condition than laymen can make through observation of his overt behavior. Once a medical or psychiatric diagnosis is made, then can the legal question of incompetency be determined by the trial court. By this time, the accused's abilities may be measured against the specific demands a trial will make upon him.^[155] (Citations omitted)

Considering the foregoing, we clarify the guidelines laid down in Formigones. Under this test, the insanity defense may prosper if: (1) the accused was unable to appreciate the nature and quality or the wrongfulness of his or her acts; (2) the inability occurred at the time of the commission of the crime; and (3) it must be as a result of a mental illness or disorder.

We now use a three-way test: first, insanity must be present at the time of the commission of the crime; second, insanity, which is the primary cause of the criminal act, must be medically proven; and third, the effect of the insanity is the inability to appreciate the nature and quality or wrongfulness of the act.

In this case, the defense failed to satisfy the tests.

Here, although the accused and his mother were presented as witnesses to prove accused-appellant's insanity, the only witness who may be considered competent to testify on the accused's state of mind is the accused's mother, Soledad. An accused whose mental condition is under scrutiny cannot competently testify on their state of insanity. An insane person would naturally have no understanding or recollection of their actions and behavioral patterns. They would have to rely on hearsay evidence to prove their claims as to what actually happened.

During cross-examination, accused-appellant testified on matters that were only related to him by others:

Q	What in particular were you experiencing at the time, reason why you consulted a quack doctor?
A	I was always out of my mind, ma'am.
Q	How did you know that you were out of your mind?
A	I do not (sic) know at that time but people told me I was out of my mind, ma'am.
Q	And these people told you that you were out of your mind during those times that you were experiencing depression, is that correct?
A	These people told me that, every time my mind was stable, ma'am.
Q	So, what in particular did those persons tell you every time your mind was stable?
A	They told me that I am doing a lot of things that I am not aware of (sic), ma'am.
Q	Can you cite some examples that was (sic) told you by the people around you?
A	They told me that I attempted to commit suicide by hanging myself by a piece of rope which I was not aware of, ma'am.[156]

Soledad may be considered as a competent witness as she has personal knowledge of her son's behavior and conduct. In her testimony, she described the recurring manic episodes of her son in the past:

Q	Being the mother, will you please describe to us how is Lito Pa a as your (sic) son?
A	He is of good character, ma'am.
Q	How about the health condition of Lito Pa a, can you describe to us his health condition prior to March 20, 2005?
A	He was not able to sleep, ma'am.
Q	Other than his failure to sleep, were there any other matter, if any, regarding the health of Lito Pa a?
A	He is (sic) always quiet, ma'am.
Q	What else, if any, can you say about the health condition of Lito Pa a?
A	As if he was always uneasy (balisa), ma'am.
Q	When did you start noticing this health problem of Lito Pa a?
A	Quite a long time, ma'am.
Q	Do you remember in what year?
A	That was year 2003, ma'am.
Q	What did you do if any to address that health condition or problem of your son Lito Pa a?
A	We brought him to a quack doctor, ma'am.
Q	Why did you brought (sic) him to a quack doctor?
A	Because as if he was out of his mind, ma'am.[157]

However, that accused-appellant was uneasy, quiet, and suffered from sleepless nights does not make him legally insane. If at all, these may only have been manifestations of unusual behavior or his alleged depression.

Aside from this, Soledad's testimony regarding her son's behavior does not relate to the time immediately before or simultaneous with the commission of the offense:

Q	You mentioned that Lito Pa a have (sic) health problems, how long have these problems occurred?
A	It started 2003 to 2004 and 2005, ma'am.
Q	Can you please describe to us the actuation of (sic) behavior of your son Lito Pa a during his health problems?
A	He was (sic) able to sleep for four (4) days and he keeps on walking for (sic) to and fro inside the house, ma'am.
Q	For how long does this period of unusual behavior takes place?
A	It takes a month, ma'am.
Q	Other than this unusual behavior, is there any basis observed by you why you said that Lito Pa a was not in his right mind during those times?
A	I always saw him sitting quietly and whenever I talked to him, he answered me differently, ma'am.
Q	You mentioned that this unusual behavior, that he was not on his right mind on (sic) 2003 to 2005. At the start of 2005 can you please describe to us the behavior of your son, Lito Pa a?
A	As if he is always not in right mind (sic), ma'am.[158]

To the contrary, accused-appellant's reaction and behavior immediately after he had killed the accused showed that he understood the wrongfulness of his action. As narrated by the police, the accused ran away to evade arrest. This, to our mind, shows that he understood the depravity and consequences of his action.

Further, the defense should have presented other witnesses who could have given a more objective assessment of the accused's mental condition such as the quack doctor who he allegedly consulted or other people from his community who had personal knowledge of his behavior.

It is highly crucial for the defense to present an expert who can testify on the mental state of the accused. While testimonies from medical experts are not absolutely indispensable in insanity defense cases, their observation of the accused are more accurate and authoritative. Expert testimonies enable courts to verify if the behavior of the accused indeed resulted from a mental disease.

While ordering a mental examination would have been valuable in this case, there were no indications that the accused-appellant was mentally ill and incompetent to stand trial. During arraignment, he was assisted by his counsel to plead not guilty to the charge. There were no motions from his counsel for the suspension of the trial or for his confinement. There was no mention of accused's erratic demeanor during trial. Further, there were no manifestations from the warden or other persons that the accused was exhibiting abnormal behavior while he was incarcerated.

The sole testimony of accused-appellant's mother was insufficient to show that his actions were caused by a mental illness. In sum, the defense failed to show clear and convincing evidence that as a result of a mental illness, accused-appellant was unable to appreciate the nature and quality of the wrongfulness of his acts at the time of the commission of the crime.

Due to the failure of the accused-appellant to prove that he was legally insane at the time of the commission of the offense, his conviction stands. However, in accordance with People v. Jugueta,^[159] this Court modifies the amount of civil indemnity from P50,000.00 to P100,000.00. Moral damages and exemplary damages of P100,000.00 each should also be awarded.

WHEREFORE, the appeal is DISMISSED. The assailed March 13, 2014 Decision of the Court of Appeals in CA-G.R. CR-HC No. 05483 is AFFIRMED with MODIFICATION. Accused-appellant Lito Pa a y Inandan is found GUILTY beyond reasonable doubt of murder and is sentenced to suffer the penalty of reclusion perpetua.

Moreover, he is ordered to pay the heirs of Sherwin Macatangay the amounts of P100,000.00 as civil indemnity, P100,000.00 as exemplary damages, and P100,000.00 as moral damages. In line with current jurisprudence, an interest at the rate of 6% per annum is imposed on all damages awarded from the date of the finality of this Decision until fully paid.^[160]

SO ORDERED.

Peralta, C. J., Perlas-Bernabe, Caguioa, Gesmundo, Hernando, Inting, Zalameda, M. Lopez, Delos Santos, Gaerlan, and Rosario, JJ., concur.
Carandang, and Lazaro-Javier, JJ., on official leave.

---

^[1] Michael L. Perlin, Psychodynamics and the Insanity Defense: "Ordinary Common Sense" and Heuristic Reasoning, 69 NEB. L. REV 3, 5 (1990).

^[2] 87 Phil. 658 (1950) [Per J. Montemayor, En Banc].

^[3] Rollo, pp. 1-A-10. The March 13, 2014 Decision in CA-G.R. CR-HC No. 05483 was penned by Associate Justice Ramon M. Bato, Jr. and concurred in by Associate Justices Rodil V. Zalameda (now a member of this Court) and Manuel M. Barrios of the Seventeenth Division, Court of Appeals, Manila.

^[4] CA rollo, p. 51.

^[5] Id. at 52.

^[6] Rollo, p. 2.

^[7] CA rollo, pp. 52-53.

^[8] Id. at 53.

^[9] Id. at 54.

^[10] Rollo, pp. 2-3.

^[11] CA rollo, pp. 56-59.

^[12] Id. at 59-60.

^[13] Id. at 60.

^[14] Id. at 51-64. The January 24, 2012 Decision was penned by Presiding Judge Rose Marie J. Manalang-Austria of Branch 87, Regional Trial Court, Rosario, Batangas.

^[15] Id. at 63-64.

^[16] Id. at 62-63.

^[17] Id. at 32-48.

^[18] Id. at 40-44.

^[19] Id. at 44-48.

^[20] Id. at 81-89.

^[21] Id. at 85-86.

^[22] Id. at 87.

^[23] Id. at 86-88.

^[24] Rollo, pp. 1-A-10.

^[25] Id. at 9-10.

^[26] Id. at 7-8.

^[27] Id. at 8-9.

^[28] Id. at 4-7.

^[29] CA rollo, pp. 107-109.

^[30] Id. at 111.

^[31] Rollo, p. 1.

^[32] Id. at 16-17.

^[33] Id. 18-27.

^[34] People v. Madarang, 387 Phil. 846, 855 (2000) [Per J. Puno, First Division].

^[35] People v. Aldemita, 229 Phil. 448, 31 (1986) [Per J. Narvasa, En Banc].

^[36] G.R. No. 87084, June 27, 1990 [Per J. Regalado, Second Division].

^[37] Id.

^[38] People v. Aldemita, 229 Phil. 448 (1986) [Per J. Narvasa, En Banc].

^[39] People v. Yam-id, 368 Phil. 131 (1999) [Per J. Melo, En Banc].

^[40] People v. Renegado, 156 Phil. 260 (1974) [Per J. Mu oz-Palma, En Banc].

^[41] REV. PEN. CODE, art. 12(1).

^[42] People v. Ambal, 188 Phil. 372, 377 (1980) [Per J. Aquino, Second Division] citing 1917 REV. ADM. CODE, sec. 1039.

^[43] Id.

^[44] Id.

^[45] See People v. Bonoan, 64 Phil. 87 (1937) (Per J. Laurel, First Division]; U.S. v. Vaquilar, 27 Phil. 88 (1914) [Per J. Trent, First Division]; U.S. v. Guevara, 27 Phil. 547 (1914) [Per J. Araullo, First Division]; U.S. v. Martinez, 34 Phil. 305 (1916) [Per J. Johnson, Second Division].

^[46] 87 Phil. 658 (1950) [Per J. Montemayor, En Banc].

^[47] Id. at 660.

^[48] Id. at 660-662.

^[49] Id. at 660-661.

^[50] People v. Rafanan, Jr., 281 Phil. 66, 78-80 (1991) [Per J. Feliciano, First Division].

^[51] Id. at 79.

^[52] See People v. Aldemita, 229 Phil. 448 (1986) [Per J. Narvasa, En Banc]; People v. Cruz, 109 Phil. 288 (1960) [Per C.J. Paras, En Banc]; People v. Rafanan, Jr., 281 Phil. 66 (1991) [Per J. Feliciano, First Division]; People v. Talavera, 413 Phil. 761 (2001) [Per J. Ynares-Santiago, En Banc]; People v. Umawid, 735 Phil. 737, 744-745 (2014) [Per J. Perlas-Bernabe, Second Division].

^[53] 281 Phil. 66 (1991) [Per J. Feliciano, First Division].

^[54] Id. at 79-80.

^[55] G.R. No. 227312, September 5, 2018, [Per J. Bersamin, First Division].

^[56] Id.

^[57] 328 Phil. 1208 (1996)[Per J. Romero, Second Division].

^[58] Id. at 1223-1224.

^[59] Id. at 1224.

^[60] Verdadero v. People, 782 Phil. 168 (2016) [Per J. Mendoza, Second Division].

^[61] Id. at 184.

^[62] Id. at 185.

^[63] See People v. Aldemita, 229 Phil. 448, 460 (1986) [Per J. Narvasa, En Banc]; People v. Puno, 430 Phil. 449 (1981) [Per J. Aquino, En Banc]; People v. Fausto, 113 Phil. 841 (1961) [Per J. Barrera, Second Division].

^[64] People v. Rafanan, Jr., 281 Phil. 66, 80-85 (1991) [Per J. Feliciano, First Division].

^[65] People v. Madarang, 387 Phil. 846, 859 (2000) [Per J. Puno, First Division].

^[66] People v. Umawid, 735 Phil. 737, 745 (2014) [Per J. Perlas-Bernabe, Second Division]; People v. Villa, Jr., 387 Phil. 155, 162-165 (2000) [Per J. Bellosillo, Second Division].

^[67] 469 Phil. 698 (2004) [Per C.J. Davide, Jr., First Division].

^[68] Id. at 712.

^[69] People v. Formigones, 87 Phil. 658, 661-663 (1950) [Per J. Montemayor, En Banc].

^[70] Id. at 662.

^[71] RITA J. SIMON AND HEATHER AHN-REDDING, THE INSANITY DEFENSE, THE WORLD OVER 6 (1st ed., 2008).

^[72] Id.

^[73] GABRIEL HALLEVY, THE MATRIX OF INSANITY IN MODERN CRIMINAL LAW 7 (1st ed., 2015); Gerald Robin, The Evolution of the Insanity Defense, 13 JOURNAL OF CONTEMPORARY CRIMINAL JUSTICE 224, 225 (1997).

^[74] People v. Ambal, 188 Phil. 372 (1980) [Per J. Aquino, Second Division].

^[75] Id. at 380.

^[76] RITA J. SIMON AND HEATHER AHN-REDDING, THE INSANITY DEFENSE, THE WORLD OVER 7 (1st ed., 2008).

^[77] People v. Madarang, 387 Phil. 846, 856-857 (2000) [Per J. Puno, First Division]; People v. Ambal, 188 Phil. 372-383 (1980) [Per J. Aquino, Second Division].

^[78] RITA J. SIMON AND HEATHER AHN-REDDING, THE INSANITY DEFENSE, THE WORLD OVER 7 (1st ed., 2008).

^[79] Id.

^[80] Id.

^[81] People v. Madarang, 387 Phil. 846, 856 (2000) [Per J. Puno, First Division].

^[82] Id. at 856-857.

^[83] Id. at 857.

^[84] RITA J. SIMON AND HEATHER AHN-REDDING, THE INSANITY DEFENSE, THE WORLD OVER 7 (1st ed., 2008).

^[85] People v. Madarang, 387 Phil. 846, 857-858 (2000) [Per J. Puno, First Division].

^[86] RITA J. SIMON AND HEATHER AHN-REDDING, THE INSANITY DEFENSE, THE WORLD OVER 7 (1st ed., 2008).

^[87] People v. Madarang, 387 Phil. 846, 858 (2000) [Per J. Puno, First Division].

^[88] R RITA J. SIMON AND HEATHER AHN-REDDING, THE INSANITY DEFENSE, THE WORLD OVER 7 (1st ed., 2008).

^[89] Id.

^[90] The Federal Insanity Defense Reform Act, (last visited September 18, 2020).

^[91] U.S. v. Freeman, 804 F.2d 1574, 1575 (11th Cir. 1986).

^[92] Eric Collins, Insane: James Holmes, Clark v. Arizona, and America's Insanity Defense, 31 J.L. & HEALTH 33, 42 (2018).

^[93] RITA J. SIMON AND HEATHER AHN-REDDING, THE INSANITY DEFENSE, THE WORLD OVER 15 (1st ed., 2008) citing the Criminal Code of Canada (RSC) C-46, 16(1), which provides:

No person is criminally responsible for an act committed or an omission made while suffering from a mental disorder that rendered the person incapable of appreciating the nature and quality of the act or omission or of knowing that it was wrong.

^[94] RITA J. SIMON AND HEATHER AHN-REDDING, THE INSANITY DEFENSE, THE WORLD OVER 73 (1st ed. 2008) citing the Criminal Code (StGB) of Federal Republic of Germany, sec. 20, which provides:

A person is not criminally responsible if at the time of the act, because of a psychotic or similar serious mental disorder, or because of a profound interruption of consciousness or because of feeblemindedness or any other type of serious mental abnormality, he is incapable of understanding the wrongfulness of his conduct or of action in accordance with his understanding.

^[95] LUIS E. CHIESCA, ET AL., THE HANDBOOK OF COMPARATIVE CRIMINAL LAW 36-37 (1st ed., 2008).

^[96] See RITA J. SIMON AND HEATHER AHN-REDDING, THE INSANITY DEFENSE, THE WORLD OVER (1st ed. 2008). It was discussed how countries such as Hungary, Israel, India, and Australia resolve legal insanity based on whether the accused understood the nature and wrongfulness of their acts.

^[97] People v. Madarang, 387 Phil. 846 (2000) [Per J. Puno, First Division].

^[98] People v. Ambal, 188 Phil. 372 (1980) [Per J. Aquino, Second Division].

^[99] People v. Valledor, 433 Phil. 158 (2002) [Per J. Ynares-Santiago, First Division]; People v. Belonio, 473 Phil. 637 (2004) [Per Curiam, En Banc]; People v. Arevalo, Jr., 466 Phil. 419 (2004) [Per J. Panganiban, En Banc].

^[100] People v. Magallano, 188 Phil. 558 (1980) [Per Acting C.J. Teehankee, First Division]; People v. Robi os, 432 Phil. 322 (2002) [Per J. Panganiban , En Banc].

^[101] People v. Rafanan, Jr., 281 Phil. 66, 85 (1991) [Per J. Feliciano, First Division].

^[102] See People v. Tabugoca, 349 Phil. 236 (1998) [Per Curiam, En Banc]; People v. Diaz, 377 Phil. 997 (1999) [Per J. Bellosillo, En Banc]; People v. Cayetano, 341 Phil. 817 (1997) [Per J. Romero, Second Division]; People v. Comanda, 553 Phil. 655 (2007) [Per J. Tinga, Second Division].

^[103] People v. Ambal, 188 Phil. 372 (1980) [Per J. Aquino, Second Division].

^[104] Id. at 382.

^[105] People v. Rafanan, Jr., 281 Phil. 66 (1991) [Per J. Feliciano, First Division].

^[106] Id. at 85.

^[107] People v. Bonoan, 64 Phil. 87 (1937) [Per J. Laurel, First Division].

^[108] 387 Phil. 846 (2000) [Per J. Puno, First Division].

^[109] Id. at 859.

^[110] People v. Aldemita, 229 Phil. 448, 456 (1986) [Per J. Narvasa, En Banc]; People v. Umawid, 735 Phil. 737, 744 (2014) [Per J. Perlas-Bernabe, Second Division].

^[111] People v. Madarang, 387 Phil. 846, 859 (2000) [Per J. Puno, First Division].

^[112] 276 Phil. 955 (1991) [Per J. Paras, Second Division].

^[113] Id. at 964.

^[114] REV. PEN. CODE, art. 12(1); People v. Ambal, 188 Phil. 372-383 (1980) [Per J. Aquino, Second Division].

^[115] AMERICAN PSYCHIATRIC ASSOCIATION, DIAGNOSTIC AND STATISTICAL MANUAL OF MENTAL DISORDERS 89 (5^th ed., 2013).

^[116] Michael L. Perlin, Psychodynamics and the Insanity Defense: "Ordinary Common Sense" and Heuristic Reasoning, 69 NEB. L. REV 3, 5 (1990).

^[117] Id. at 5.

^[118] People v. Bascos, 44 Phil. 204 (1922) [Per J. Malcolm, First Division].

^[119] Id. at 206.

^[120] Id. at 205-206.

^[121] 64 Phil. 87 (1973) [Per J. Laurel, First Division].
 
^[122] Id. at 91-93.

^[123] Id.

^[124] People v. Dungo, 276 Phil. 955-969 (1991) [Per J. Paras, Second Division].

^[125] See People v. Danao, 290 Phil. 296 (1992) [Per J. Nocon, Second Division]; People v. Cordova, 296 Phil. 163 (1993) [Per J. Davide, Jr., Third Division]; People v. Yam-id, 368 Phil. 131 (1999) [Per J. Melo, En Banc]; People v. Domingo, 599 Phil. 589 (2009) [Per J. Chico-Nazario, Third Division].

^[126] See People v. Robi os, 432 Phil. 322 (2002) [Per J. Panganiban, En Banc]; People v. Florendo, 459 Phil. 470 (2003) [Per J. Bellosillo, En Banc]; People v. Tibon, 636 Phil. 521 (2010) [Per J. Velasco, Jr., First Division]; People v. Bulagao, 674 Phil. 535 (2011) [Per J. Leonardo-De Castro, First Division]; People v. Isla, 699 Phil. 256 (2012) [Per J. Mendoza, Third Division]; People v. Umawid, 735 Phil. 737 (2014) [Per J. Perlas-Bernabe, Second Division]; Verdadero v. People, 782 Phil. 168 (2016) [Per J. Mendoza, Second Division]; People v. Roa, 807 Phil. 1003 (2017) [Per J. Velasco, Jr., Third Division]; People v. Pantoja, 821 Phil. 1052 (2017) [Per J. Martires, Third Division]; People v. Haloc, G.R. No. 227312, September 5, 2018, [Per J. Bersamin, First Division]; and People v. Mira a, 831 Phil. 215 (2018) [Per J. Martires, Third Division].

^[127] People v. Austria, 328 Phil. 1208 (1996) [Per J. Romero, Second Division].

^[128] 636 Phil. 521 (2010) [Per J. Velasco, Jr., First Division].

^[129] Id. at 530-531.

^[130] See People v. Embalido, 58 Phil. 152 (1933) [Per J. Abad-Santos, En Banc].

^[131] See People v. Talaboc, Jr., 140 Phil. 485 (1969) [Per J. Sanchez, En Banc]; People v. Berio, 59 Phil. 533 (1934) [Per J. Diaz, Second Division]; People v. Hisugan, 201 Phil. 836 (1982) [Per J. Relova, First Division]; People v. Gelera, 343 Phil. 225 (1997) [Per J. Puno, Second Division]; Galang v. Court of Appeals, 381 Phil. 145 (2000) [Per J. Pardo, First Division]; People v. Atienza, 201 Phil. 844 (1982) [Per J. Relova, Second Division].

^[132] Almeda v. Court of Appeals, 336 Phil. 621 (1997) [Per J. Francisco, Third Division]; Masipequi a v. Court of Appeals, 257 Phil. 710 (1989) [Per J. Cortes, First Division]; People v. Olarbe, G.R. No. 227421, July 23, 2018, 873 SCRA 318 [Per J. Bersamin, Third Division].

^[133] People v. Retubado, 463 Phil. 51 (2003) [Per J. Callejo, Sr., Second Division].

^[134] People v. Castillo, 553 Phil. 197 (2007) [Per J. Ynares-Santiago, Third Division].

^[135] Verdadero v. People, 782 Phil. 168, 170-171 (2016) [Per J. Mendoza, Second Division].

^[136] See People v. Dungo, 276 Phil. 955 (1991) [Per J. Paras, Second Division]; People v. Yam-id, 368 Phil. 131 (1999) [Per J. Melo, En Banc]; People v. Bonoan, 64 Phil. 87 (1937) [Per J. Laurel, First Division]; People v. Ambal, 188 Phil. 372 (1980) [Per J. Aquino, Second Division]; People v. Florendo, 459 Phil. 470 (2003) [Per J. Bellosillo, En Banc].

^[137] Julie E. Grachek, The Insanity Defense in the Twenty-First Century: How Recent United States Supreme Court Case Law Can Improve the System, 81 INDIANA LAW JOURNAL, 1479, 1487 (2006).

^[138] Nancy Haydt, The DSM-5 and Criminal Defense: When Does a Diagnosis Make a Difference? 2015 UTAH LAW REVIEW 847, 848 (2015).

^[139] Julie E. Grachek, The Insanity Defense in the Twenty-First Century: How Recent United Sates Supreme Court Case Law Can Improve the System, 81 INDIANA LAW JOURNAL 1479, 1490 (2006).

^[140] RULES OF COURT, Rule 130, sec. 50(c).

^[141] See People v. Austria, 328 Phil. 1208 (1996) [Per J. Romero, Second Division].

^[142] People v. Estrada, 389 Phil. 216 (2000) [Per J. Puno, En Banc].

^[143] 192 Phil. 430 (1981) [Per J. Aquino, En Banc].

^[144] People v. Austria, 328 Phil. 1208 (1996) [Per J. Romero, Second Division].

^[145] AMERICAN PSYCHIATRIC ASSOCIATION, DIAGNOSTIC AND STATISTICAL MANUAL OF MENTAL DISORDERS 25 (5^th ed. 2013).

^[146] CHARLES SCOTT, DSM-5 AND THE LAW 136-137 (1st. ed. 2015).

^[147] Nancy Haydt, The DSM-5 and Criminal Defense: When Does a Diagnosis Make a Difference? 2015 UTAH LAW REVIEW 847, 856 (2015).

^[148] Id.

^[149] 389 Phil. 216 (2000) [Per J. Puno, En Banc].

^[150] Id. at 237-238.

^[151] People v. Estrada, 389 Phil. 216 (2000) [Per J. Puno, En Banc]. See also People v. Serafica, 139 Phil. 589 (1969) [Per J. Dizon, En Banc].

^[152] Id. at 238.

^[153] Id. at 241.

^[154] Id. at 242.

^[155] Id. at 241.

^[156] CA rollo, pp. 42-43.

^[157] Id. at 40-41.

^[158] Id. at 41.

^[159] 783 Phil. 806 (2016) [Per J. Peralta, En Banc].

^[160] See Nacar v. Gallery Frames, 716 Phil. 267, 281-283 (2013) [Per J. Peralta, En Banc].