Discussion

To our knowledge, we report the first case of complex fatal self-harm associated with psilocybin ingestion in an individual with no known prior suicidality. The first method of self-harm that was employed was the infliction of incised wounds to the neck, forearms, and elsewhere. This was followed by the concomitant application of a black plastic garbage bag over the head with occlusion of its mouth around the decedent's neck by an electrical cord as a ligature to effect plastic bag asphyxia-facilitated hanging, with the electrical cord on the external aspect of the bag.

The features of the incised wounds of the neck and forearms indicated self-infliction at sites of predilection for intentional incisional self-harming injury. In terms of chronology, the presence of blood on the in situ electrical cord ligature around the decedent's neck is consistent with the decedent having placed it after he had sustained the incised wounds. Analysis of the urine identified the presence of psilocin; however, it was not possible to quantify psilocybin in the blood. The presence of psilocin in the urine can only be accounted for by metabolism of psilocybin in the blood. The disarray of the scene is in keeping with the psychological effects of psilocybin intoxication.

Complex suicidal (intentional fatal self-harming) deaths can be classified as (i) planned or unplanned or (ii) primary or secondary. Complex suicides are deemed as primary when the self-harming modalities are applied simultaneously or secondary when the self-harming modalities are applied in chronological succession. 13 The current case describes the use of three modalities that consist of infliction of incised wounds, plastic bag asphyxia, and hanging. The presence of incised wounds prior to completion of the suicide attempt is in keeping with published reports of secondary unplanned complex suicides. 13 In these cases, it is theorized that excessive pain or the failure of the original method results in a change in suicide modality. Similarly to this case, incised wounds were more frequently followed by hanging. 13 However, it is worth noting that the combined use of plastic bag asphyxia and hanging possibly represents a planned primary component. 13 Nonetheless, complex suicides can present a challenge in forensic pathology as they may raise the suspicion of homicide. As reported here, the nature of the injuries at autopsy and the findings of the scene examination confidently establish their self-inflicted nature and chronology of the applied self-harm modalities to effect them.

The decedent was not known for suicidal ideation or prior attempts, in keeping with prior psilocybin-associated case reports.9,12 However, psilocybin is generally associated with a reduced risk of suicidal behaviors.6,14 A previous survey has shown that the risk of harm increases with higher doses of psilocybin, prolonged duration of the experience, and lack of a supporting environment. 7 In this case report, the decedent was at increased risk due to the lack of social support during ingestion. Due to the lack of a quantified blood psilocybin concentration, we are unable to ascertain the possible contribution of the dose. The importance of a safe environment with psychological support is often emphasized in clinical studies, but despite this, a clinical trial with treatment-resistant depression reported increased suicidal behaviors and ideation in their high-dose psilocybin treatment arm.15,16 Currently, the Canadian Network for Mood and Anxiety Treatments recommends that psilocybin can only be considered an experimental treatment due to a lack of high-quality evidence of its safety and efficacy. 17

Manner of Death Considerations

Suicide as a manner of death requires demonstrated intent to fatally self-harm and a standard of proof that exceeds other competing possibilities. 18 However, fatal self-harming that occurs in the context of drug intoxication without any demonstrated prior intent to take one's life raises the question as to the true underlying reason for the fatal self-harming. Indeed, a previous case report of an individual without a psychiatric history who presented with self-harming behavior in the context of psilocybin ingestion was unable to prove intent of “suicide attempt” upon recovery. 12

In forensic pathology practice, there are divergent views regarding the role of intent when certifying suicide as the manner of death. Within the framework proposed by the National Association of Medical Examiners (NAME) for manner of death classification, engaging in an inherently dangerous volitional act implies accepting the risk of death as the “sub-intent” of the act. 18 This perspective allows classification of the manner of death as suicide even when the decedent's state of mind and intent to die are difficult to establish. This scenario is similar to Russian roulette, where the act of placing a loaded firearm to the head is inclusive of accepting a definite risk of death when the trigger is depressed, and deaths occurring in this setting are commonly classified as suicide by convention. 18

However, when concomitant drug intoxication is present, the general recommendation proposed by the NAME is to classify the death as suicide because the effects of intoxication on judgment and behavior are argued to be inherently subjective. 18 Analogous scenarios include when suicide is achieved under the influence of ethanol in hanging, descent through a height, or jumping in front of a train.

It has been argued that diminishing the role of intent does not remove the need to infer the decedent's mental state but instead redirects the inference toward volition. 19 In other words, there remains the need to infer the determination to perform the act rather than the specific reason for the act itself. Therefore, it has been proposed that intent should remain integral to the manner determination of suicide to remain consistent with the term's common meaning. 19 Although the determination of intent is inherently subjective, it can be inferred through the integration of medical history, circumstances of death, scene investigation, and autopsy findings. 20 This process is analogous to the clinical judgment used by clinicians when a patient's history is incorporated to rank the most probable differential diagnoses in order of investigative importance. Ignoring such contextual information may therefore be inappropriate, similar to disregarding travel history in a patient presenting with fever that may be infectious in origin. 20 In the present case, the combination of an absence of established prior suicidal ideation, toxicological evidence of psilocybin ingestion, and the disorganization observed at the scene all support the possibility that the complex fatal self-harming was precipitated by the pharmacological effects of the drug. Despite the volitional act of self-harm, it is difficult to determine the intent of the act, and the terminology “self-harm” has therefore been used preferentially in our discussion instead of suicide.

In Canada, the standard of proof for certification of suicide as the manner of death is grounded in case law 21 at what is known as the Canadian civil standard of proof and is on the balance of probabilities (more likely than not; greater than 51%) as stated in the NAME Guidelines. 18 Although this is the required standard, in practice coroners and medical examiners rarely classify a death as suicide unless there is clear evidence of intent. In some jurisdictions, case or other law requires a preponderance of evidence (greater than 70%) to exist for a classification of suicide as a manner of death. 18

This case was performed in a (medical) coroner's jurisdiction in Canada with the coroner having statutory responsibility for certifying both cause and manner of death. Despite the offered forensic pathology opinion of suicide as the manner of death (akin to an ethanol-intoxicated individual ending their life by hanging or a methamphetamine-intoxicated individual jumping off a building in the belief that he/she could fly), the manner of death was ultimately certified as Undetermined by the investigating coroner following consultation with the regional supervising coroner.