‘When I use a word,’ Humpty Dumpty said, in a rather scornful tone,’ it means just what I choose it to mean, neither more nor less.”The question is,’ said Alice, ‘whether you can make words mean so many different things.’

‘The question is,’ said Humpty Dumpty, ‘which is to be master – that’s all.’

Lewis Carroll – Through the Looking Glass

“I have always been worried about cannabis, with this new skunk, this more lethal part of cannabis,”

“I don’t think that the previous studies took into account that so much of the cannabis on the streets is now of a lethal quality and we really have got to send out a message to young people – this is not acceptable.”

Gordon Brown – speaking on GMTV

In every dictionary I’ve ever owned the adjective ‘lethal’ has had the same meaning, ‘of, pertaining to, or causing death’, so I was naturally rather intrigued to find Gordon Brown referring to skunk as the ‘more lethal part of cannabis’ and as being ‘of a lethal quality’.

Is he right, and if so did I miss the recent epidemic of stoners dropping dead on the way to the fridge in search of the last Mars bar?

Just how lethal is cannabis?

Well, why don’t we take a look at the statistics, and in this case we’re looking at a dataset entitled ‘Deaths related to drug poisoning, England and Wales‘, which is published by the Office of National Statistics, covering the period from 1993 to 2006.

Before we start there are, for reasons of accuracy and clarity, a couple of things worth noting.

First, the data we’re looking at relates only to controlled substances, prescription drugs and over the counter medicines such as paracetamol, codeine and the like. Deaths attributable to alcohol or tobacco are not included in the data, other than where the consumption of alcohol has been recorded as a contributory factor alongside another drug.

Second, and quite obviously following on from the first point, we are also not dealing here with the question of cancers linked to the use of cannabis, only those instances in which cannabis us has been cited on a death certificate as the cause of death or as a contributory factor in a death.

Before we get on to cannabis, specifically, we should also get a general picture of drug-related mortality and how the general longitudinal trends have been shaping up, to which the answer is not that badly.

Looking at the data for all drug-related deaths, we started out in 1993 with 2178 deaths and an upward trend which peaked between 1999 and 2001 at around 3100 deaths in the worst years (1999 and 2001). Since then the trend has started to move downwards again, falling to 2,570 deaths in 2006.

To put that into perspective, around half a million people die in the UK every year, so we’re looking at 0.5% of all deaths.

So far as accounting for the general trend in terms of specific drugs, I’m sure it’ll come as no great surprise that the drugs that have the most significant impact on the death statistics are the opiates, heroin and morphine, and the heroin substitute, methadone. These currently account for around 35-40% of all drug-related deaths and the correlation between opium-related deaths and the general statistics for all drug-related deaths is strong enough to predict that any significant movements in the general statistics, upwards or downwards, will be overwhelmingly as a result of changes in patterns of opiate use.

Looking at the data for other drugs show most as either stable or on a downward trend, particular when it comes to some of the more popular choices for suicides such as tranquilisers, anti-depressants and paracetamol, with the only drugs bucking the trend being ecstasy (MDMA), which shifted upwards sharply in 2001 from around 25-30 deaths a year to around 55-60 death as year, where things have stabilised ever since, and cocaine, where there is a rising trend from 27 deaths in 1998 up to 190 deaths in 2006.

Against all that, the number of deaths in which cannabis is cited as a causal factor has bumped steadily along at an average of 14 deaths a year for the whole 14 years covered by the data with the exact number of deaths varying from a minimum of 8 (in 1999) to a maximum of 19 (in 1994, 2004 & 2005).

Of the 193 deaths over the last 14 years in which cannabis was cited as a contributory factor on the death certificate there were only 12 in which it was the only drug cited, compared to 75 deaths over the same period in which cannabis was cited alongside alcohol. In the remaining 106 deaths cannabis was cited alongside one or more other drugs, and although no breakdown of this is given.

Now, according to a Home Office study released earlier this year:

…skunk cannabis accounted for 15 per cent of the drug’s usage in England and Wales in 2002. That figure is now 75 per cent to 80 per cent. About 300 cannabis samples seized on the streets since the start of this year showed levels of skunk, or sinsemilla, had rocketed.

In contrast the prevalence of milder cannabis resin fell from 60 to 70 per cent of the market in 2002 to 20 per cent.

So, one would assume that if skunk really is a more lethal form of cannabis, then this should be reflected in the death statistics, for which we will take 2002 as the pivot around which we’ll make or comparison, in line with the information on changes in the market for cannabis indicated by the Home Office.

During the period from 1993 to 2001, there were 114 deaths in which cannabis was cited on the death certificate, and average of just under 13 deaths a year. Between 2002 and 2006, there were 74 such deaths at an average of just under 16 a year, so it would appear that there has been some increase in deaths over the last five years, but only a very small increase and one that it is impossible to ascribe to the growth in the use of skunk over that period. After all, in only 6% of cases over the whole 14 year period for which we have the statistics, was cannabis the only drug cited on the death certificate, and if one looks at the data for deaths in which both cannabis and alcohol were cited one find that these averaged only 4-5 a year up to 2002 but have averaged just under 7 a year since 2002.

Can we say, conclusively, from that information that its the changing patterns in cannabis use that has caused that increase, or could it just as easily be related to changing patterns in the use and abuse of alcohol?

Based on the information we have, we cannot say for sure, but what we can be sure of is that cannabis was cited as a contributory factor in only 17 deaths in the UK in 2006, of which only two cited cannabis alone.
There is absolutely no evidence to support Brown’s assertion that skunk is in any sense a more lethal form of cannabis, which I guess means that, Humpty Dumpty, he believes that the word lethal means just exactly what he chooses it to mean, neither more nor less.