'Comparing cannabis with tobacco'. Henry JA, Oldfield WLG, Kon OM. BMJ (2003) 326: 942-943
I would commend these authors on using the correct scientific term cannabis, unlike some colleagues who seem to prefer terms allegedly introduced by governments rather than scientists.
That said, this is one of the most un-scientific BMJ articles I have read. Despite their being opposites in most respects, Henry and co-authors try to compare cannabis and tobacco. While both are common psychoactive drugs, cannabis is a relaxant, tobacco a partial-stimulant. One is highly addicting, the other is not. One has been prescribed by physicians down the ages and continues to be recommended in certain clinical circumstances by doctors of good repute. Hence a 'comparison' is an intriguing concept unless clearly stated objectives are being examined (eg. dependency, mortality, side effects, beneficial effects, etc).
Cannabis has an extremely low mortality while tobacco's toll is legion. Nearly 20,000 Australians die from tobacco related disease each year with few if any cannabis reported deaths.
When examining any drug, one looks for costs and benefits but these authors have only looked for 'costs' and, for cannabis, then they can only point to 'associations'. Even if cannabis actually caused some cases of mental disease (and it does induce dependency in a small proportion of heavy users), the drug may also alleviate some conditions such as anxiety, insomnia, depression, anorexia or chronic pains.
These authors state that it might be seen as 'scaremongering' to speculate on the basis of cannabis being of equal toxicity as tobacco ... yet they go ahead and do just that: "the corresponding figure for deaths among 3.2 million cannabis smokers would be 30,000" [annually in the UK]. Can these authors be serious when no group of suspected cases is yet to be reported after the drug has been used for thousands of years in western society? If they are interested in speculation, why don't they look at alcohol consumption in cannabis smokers?
Quite apart from their tenuous position in trying to point to cardiovascular complications which may occur with smoking cannabis, they make numerous questionable and unreferenced statements in their paper including the howler about cannabis strength increasing over the years (by 10 to 20 times!). Even if this were true, it would mean less by-products for the same amount of drug and thus possibly safer smoking. Also, cannabis can be taken orally with no effect on the lungs at all, but these authors do not canvass that issue, nor other harm reduction steps. Without references, they also quote "Nederweed" ('the variety smoked in the Netherlands') which they claim has an *average* of 10-11% tetrahydrocannabinol. This is obviously unhelpful since Holland, like other countries, has a variety of cannabis and resins available on the market, including cannabis cookies.
These authors make much of the increase in cannabis use and the reductions in tobacco consumption in recent years. However, they are not open enough to discuss the legal status of the drugs. If these authors are honestly concerned about harms from cannabis then it is hard to understand why they would ignore the spectacular failing of current prohibitions in addressing these harms. The results of long term cannabis decriminalization (eg. South Australia, Holland) are equally ignored by these 'scaremongers' (to use their own term).
comments by Andrew Byrne ..
http://bmj.com/cgi/content/full/326/7396/942
