No good evidence for legalising medicinal cannabis

The speed with which our legislators have taken to heart a proposal to legalise medicinal cannabis smacks of undue haste and a pandering to fashion.

Despite its glaring flaws, the Dáil has allowed the Cannabis for Medicinal Use Regulation Bill to proceed to committee stage, and six political parties have declared themselves in favour of its proposals. Even Minister for Health Simon Harris, anxious to please everyone in the House, couldn't bring himself to spoil the mood, despite having serious concerns about the measures proposed.

This in spite of the fact that the Bill, as it stands, would make cannabis legal for everyone over the age of 16, including for recreational use.

It is as though the challenges of the health service – the elderly spending days on trolleys, the exodus of highly-qualified staff, the half of a million people on waiting lists – don’t exist. Unable to solve the big problems, the politicians’ response is to give us yet more drugs, ones with obvious negative side effects. Let them smoke pot, suggests the Bill – as long, as its cut-and-paste provisions specify, as it doesn’t contain nicotine, carries a sell-by date and gluten-free sticker, and, yes, is medically indicated.

Small studies

Why the hurry? Many claims are made for the benefits of cannabis used for medical purposes, but most of the studies done so far are small, short-term and of poor quality. Anyone can trawl the internet and seize on research to their liking, yet the balance of medical opinion on medicinal cannabis suggests the jury is out.

The Cochrane Library, for instance, is a respected independent collaboration of researchers that brings together existing knowledge on particular medicines and attempts to form an overall conclusion on their usefulness for particular conditions.

Here is what its reports say about cannabis medications. They “may be useful” for treating nausea and vomiting caused by chemotherapy; no reliable conclusions can be drawn as a treatment for epilepsy; no convincing evidence in relation to treating fibromyalgia; limited and inconclusive results in relation to the treatment of schizophrenia.

Hardly a resounding thumbs-up. And yet absence of evidence is not the same as evidence of absence of benefit. It may well turn out that rigorous long-term studies into the use of cannabis-containing substances for specific disorders will show evidence of benefit. We just aren’t there yet.

Neurologist and epilepsy specialist Dr Colin Doherty summed up current knowledge at a recent Dáil committee: "Already, it is possible to state with confidence that this drug will not work for everyone, will cause intolerable, but probably not dangerous, side effects in a few; but for those for whom it will work it may be lifesaving".

Anecdotal claims

And yet the debate has seen all manner of anecdotal claims made for various substances in the treatment of various conditions, regardless of the composition of the drug, the severity of the condition involved or whether they are intended for children or adults.

Proponents of this measure talk down “conventional medicine”, preferring to ignore the fact that we have good reasons for applying stringent rules to the use of all medicines. These rules license drugs at specific strengths for the treatment of specific conditions, rather than allowing a one-size-fits-all approach, as is being proposed.

Indeed, these rules have been applied in the case of one cannabis-containing product, Sativex, which has been licensed for use in Ireland.

While “Big Pharma” is decried, the campaign for liberalisation has used remarkably similar tactics to that employed by the industry by pushing individual patient stories to the fore of the debate.

Cannabis-containing products, like any other drugs, will have to show they produce a benefit, and that they are not harmful for patients. And yet we know that cannabis has harmful side effects. It is addictive, it can harm your mental health and may affect your fertility (says Britain’s NHS). There may well be other products that can match any positive effects without this drawback.

Modern Ireland likes to show the world it is progressive, but this isn’t like banning plastic bags or workplace smoking, because neither of those measures had any downsides.

It is also claimed cannabis is less harmful than alcohol or tobacco. Maybe so, but why make another harmful substance available when we are trying to restrict access to other threats to our public health?

It is hard to avoid the conclusion that this Bill has as an additional, or even a principal, goal the normalisation of cannabis. Once medicinal cannabis is legalised, it will become even harder to enforce the existing laws banning its use for recreational purposes. Is this really what we want?