ONE OF THE core mantras of enthusiasts for the world’s most popular illicit drug is that cannabis never kills its users.
It’s hard to argue with that assertion, especially in the USA where many physicians and politicians have endorsed – or at least, not opposed - the legalisation of marijuana in 38 states for medical use, and 24 states for recreational use.
On this side of the pond, the argument is a little fuzzier, with twenty or more death certificates mentioning cannabis in ‘drug-related deaths’ annually in our near-neighbours England and Wales. Nonetheless, over 20 European countries have introduced legislation to permit the medicinal use of cannabis, and gradual legalisation seems inevitable.
I’m a fan of piloting changes like drug liberalisation but what medics like me mostly worry about is the issue of cannabis-related violence and especially homicide, because while cannabis may rarely kill, cannabis users frequently do.
Now, enthusiasts usually snort with derision when I make that assertion and rehearse the hippy-ish notion that ‘weed’ only makes for mild and ‘mellow’ people. And I too used to believe that until three things happened: my own friends from the 1970s developed serious complications from their cannabis use; I spent decades in emergency departments dealing with industrial levels of drug toxicity; and – most strikingly – I studied the role of drug-fuelled violence in wartime, starting with Vietnam, that defining conflict of my youth.
For those reasons in particular, the massive surge in use of all drugs in recent years in this country seems problematic. Cannabis is now the most popular recreational drug in Ireland, after ethanol and nicotine (all three often being consumed together), a popularity that may be generally attributed to our current affluence, our relatively youthful population, and the easy availability of all drugs.
In the case of weed, specifically, the ready access can be attributed to hydroponic technology and excellent growing conditions, globalisation, and the vast profits to be made in its sale. But another, arguably pivotal, factor in the widespread consumption of cannabis is the misinformation surrounding its side effects, especially on mental health, which includes a sort of ‘anti-vaxxer’ level of hostility to public education about the drug by psychiatrists, GPs or emergency physicians – in other words, those who deal with the toxic complications of weed, like anxiety/depression in teenagers, addiction, vomiting, hallucinations and violence – the latter being a truly worrying issue at present.
Now enthusiasts will rightly ask, where’s the evidence for all this violence? And I’d admit that – as yet – there isn’t a great deal of rigorous scientific evidence, beyond surveys of health professionals and users, and a growing number of case reports.
For instance, in the past year or so in Ireland, there have been at least three homicides where the perpetrator was alleged to have had a catastrophic cannabis-related psychosis, including Diego Costa Silva, who decapitated his wife Fabiola De Campos Silva; James Kilroy, who savagely slaughtered his wife, Valerie French; and Christina Anderson, who stabbed a neighbour, Gareth Kelly, to death over an ‘issue with parking’ outside her house. In a further two, the court heard evidence that psychotic episodes may have been triggered or exacerbated by drug use, including cannabis: Richard Burke who beat his on-off partner Jasmine McMonagle to death in her home while her two daughters were asleep upstairs; and Stephen Silver, who shot Garda Colm Horkan dead with the garda’s own gun.
At least two other comparable cases are currently before the courts in this jurisdiction, but there have been countless other cases in the anglophone media in the recent past – for instance, in Portadown, Nottingham, Sydney and Los Angeles - describing appalling savagery, often involving kitchen knives, daggers and swords, where the perpetrator was either a regular or occasional consumer of cannabis.
Most of the recent cases of cannabis-related psychotic killings here have involved intense medico-legal debate about the definition of insanity, which often entailed a plea by defence lawyers that their client did not know what they were doing at the time of the killing, and thus may have been culpable of manslaughter but not (‘intentional’) murder.
The ‘not knowing’ argument applied to Celyn Eadon who killed his mother Noreen Kelly in a frenzied drug-fuelled attack in her Mayo home in 2011, during which he stabbed her 19 times. Initially found guilty of murder unanimously by a jury, his conviction was subsequently overturned by the Supreme Court, when the State accepted his plea to the lesser offence of manslaughter. His lawyers argued that “gross intoxication” was not an excuse for their client’s actions but it had deprived him of an intention to kill and cause serious injury to his mother.
The ‘not stopping when you (should) know that drugs can impair your thinking’ argument applied to James Kilroy, who brutally killed his wife Valerie French (also in Mayo) in 2019, while in the grip of a cannabis-induced psychosis, after years of using weed. The presiding judge, Mr Justice Hunt recently said that ‘the wording of the Criminal Law (Insanity) Act does not allow a defence where a mental disorder is brought on by drug use’.
Crucially, he said the removal of responsibility for criminal acts under the Act is designed for people who are ill, “not those who get in a state on a self-induced basis”. While it did not apply in this case, he might also have added that substance misuse greatly increases the risk of homicidal violence when the user has a serious underlying psychiatric illness, like schizophrenia.
I suspect that the medico-legal tug-of-war will continue for the foreseeable future in relation to drug-related killings in this country and others, as defendants claim that they were – often temporarily – insane due to drug intoxication, and lawyers argue over the wording of the relevant legislation. I also believe that ‘senseless’ or ‘inexplicable’ killings by people who are deranged because of the use of drugs like cannabis will rise relentlessly in the next few years. So here’s what I consider to be the three key steps to addressing the problem of cannabis-related violence:
Establish the scale of the problem: A 2022 paper suggested that over 94,000 of the Irish population were likely to have a cannabis use disorder (CUD) which multiplies the risk of psychosis, while over 4,700 people started treatment for cannabis addiction. This is a starting point for estimating the risk of cannabis-induced violence, which usually involves paranoia, delusions and agitation. However, it must be remembered that for each psychotic killing there will be many cases of sub-lethal violence to others.
Remember that most medical science starts with case reports, followed by increased awareness, systematic testing, and then policy development. The same needs to happen in Ireland with systematic toxicology testing of all those suspected of extreme (and certainly lethal) violence. We already do this with car drivers, so the technological and legal precedents exist. Only with adequate data can we address the problems like the violence so often correlated with drug use.
Before we further liberalise drug availability, we need better data on drug-related health issues, and the capacity to manage the complications of excessive drug use. It should also be clear to all that there isn’t the mental health service or emergency department capacity in this country to adequately deal with the many drug-using mentally ill people on our streets at present.
Finally, when you next hear about an act of ‘senseless savagery’, especially involving a bladed weapon, you should probably not suspect terrorism, at least not immediately, but a drug-induced psychosis.
Moreover, remember that every one of the killers named above were probably advised, or begged, to reduce their cannabis (and other intoxicant) consumption by those who loved them, and – tragically – those whom they killed. Enthusiasts often deride the use of ‘fear-based’ propaganda in relation to drug education.
My response is to say: remember the terror of those who were killed by psychotic drug users. Consider the fear that hundreds of others continue to endure as they deal with their addicted or agitated loved ones. Remember that drug education hasn’t obviously reduced the use of drugs in this country or the one next door. Then think of the old motto: “We only really learn the hard way”.
Dr Chris Luke is a columnist, author and a retired consultant in emergency medicine
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