Friday, 22 July 2011

One Man's Poison

The previous post deals with the issue of cannabis legalisation policy approached as broadly speaking a matter of weighing costs and benefits. Here I'll make some first steps in discussing the relevance and impact of moral principles.

(My comments about Hitchens's position are inevitably somewhat sketchy; one could go on for thousands of words attempting to cover every fine gradation and distinction in the positions it is possible to take. An advantage of adversarial debate is at least that I can rely instead on Hitchens to clarify which positions he wishes to appeal to.)

A successful appeal to moral principle in this debate should establish two things: that the principle is valid, and that it has certain consequences so far as the criminal law is concerned. That is not, however, to say that either of these things must be established to any particular standard or by any particular method: perhaps the most that can be said here is that good reasons must be supplied. If they are not, the argument won't go through. And if a (supposed) moral principle can be shown to be invalid or legally inconsequential, then arguments invoking it can be rejected outright.

Tuesday, 19 July 2011

What is To Be Done?

The present debate is about the legal status of cannabis. The topic is not itself whether smoking cannabis is an especially good idea, or the kind of thing everyone should do, or harmful, or beneficial. None of these will decide the question of legalisation and prohibition, certainly not on their own.

I do not believe any harmful effects to the user that might plausibly be discovered would be a sufficient justification for bringing to bear the power of the state to criminalise the possession and use of cannabis. Nonetheless, for those who disagree or whose attitude to cannabis has otherwise been shaped by highly exaggerated warnings, I've explained my reasons for thinking that the mental health risks from taking cannabis are minimal. I don't propose to go into those any further here.

The first issue I'll deal with is the burden of proof - in the first place, it seems clear to me that any exertion of state penal power over the individual requires justification. Hitchens advocates instituting a much harsher punitive regime than the present one, which already imprisons, fines, and brands as criminal a large number of users. One might suggest that the status quo is privileged, that any departure requires positive justification, but that need not concern us since neither Hitchens nor I consider the current position acceptable.

The 'precautionary principle' - that where it seems possible that a course of action may cause harm, the course should not be adopted - is of little help here - or for that matter in general - since unless unfounded fears are allowed to prevent any change, the 'possible' harms must in fact be probable to a sufficient degree, and since there will be pros and cons on both sides, the question rapidly becomes - which is to be preferred? The harmful effects of the present regime, and of the much harsher regime Hitchens advocates, are clear - imprisonment is a major harm in itself to individuals and those close to them, and while relatively few may be prosecuted, many more take furtive and burdensome steps to avoid it - which accounts on large part for the relatively low rate of conviction. And those who do not share the conviction that cannabis is an innocent herb may not appreciate the resentment, and perception of victimisation that this involves.

I've previously mentioned the harmful effects of the lack of regulation which comes with less-than-completely effective prohibition. These would occur even if possession and use were to be entirely decriminalised. Criminal gangs and unscrupulous dealers will sell to any age group and freely adulterate a product which in any case cannot be checked for strength or specific constituents (for example, one might wish to ensure that one's cannabis contained a relatively high proportion of cannabidiol).

Sunday, 17 July 2011

CANNABIS CANCER CURE? - More on scientific evidence

As promised, here is a detailed look at some prominent and relatively recent studies. I've restricted myself to two such studies, both of which have Murray's fingerprints on them. I haven't gone further because this kind of analysis is relatively time-consuming and I want to lay the issue to rest as quickly as is possible consistently with answering Hitchens's challenge to explain my views on harm.

While I've tried to avoid selecting straw men for this analysis, I haven't been terribly rigorous in my selection criteria - the selection is in any case limited by the need to choose studies which are freely available to, thus checkable by, the public. To address this potential source of actual or perceived bias, I will make this commitment: should Hitchens care to propose, in comments to this post, any other paper which he considers invulnerable to my objections, or should any author of a paper on the topic propose theirs, I will respond with a post dedicated to analysing that paper.

The two papers represent the two specific sources of error which I discern in this area of research: first, the existence of a common predisposition, in the sense outlined previously, that influences both cannabis use and the emergence of schizophrenia; and second, the confusion of transient cannabis-related phenomena with evidence of schizophrenia.

Before proceeding, I'll mention two other matters.

First, a merely illustrative example of the context in which this research is proceeding. A review paper published in the Lancet, Moore et al., Cannabis use and risk of psychotic or affective mental health outcomes: a systematic review, states that

There is now sufficient evidence to warn young people that using cannabis could increase their risk of developing a psychotic illness later in life.

This is of some interest for two reasons: first, the statement is couched in terms which suggest that a long-sought objective of gaining 'sufficient evidence' has been reached. Second and perhaps more importantly, the standard of evidence reached is low. The best that can be said is that it is sufficient to warn young people that using cannabis could increase their risk. If doctors are to warn of everything that 'could increase risk', they are going to be spending a lot of time issuing warnings.

Cannabis and cancer

Second, in my previous post I did my best to answer Hitchens by honestly laying out the strongest case against cannabis that I consider justified. I said I've already mentioned that smoking cannabis carries a risk of cancer. It hardly need be added that I would assume it imposes the other major risks associated with smoking. In any case, in Europe cannabis is most commonly smoked mixed with tobacco

These remarks were cursory, since my primary concern was not with any cancer risk (as indicated by the quote I supplied from Hitchens: As for the risk of cancer, while it undoubtedly exists, it is not my principal concern).

Since reading my previous post, Hitchens has shown some early signs of shifting his emphasis - as is his unquestioned prerogative - from mental health to smoking-related dangers. In a recent comment he states: As for cannabis being a poison, it is plainly injurious to its users in many ways, especially when smoked ( as Mr Wilkinson concedes in his latest posting).

So to nip this in, so to speak, the bud, I'll slightly expand and clarify my remarks on cancer and cannabis. Any smoking almost certainly imposes - causes - an increased risk of cancer. Many things contain carcinogens (I seem to remember reading that bracken is among them). Smoke and other products of burning organic matter are among these: smoked meats and burned toast are believed to increase cancer risk, for example. So the likelihood is that cannabis smoke does the same. However, Cancer Research UK make it clear that the specific risks of cannabis smoke are not understood and are probably lower than those of tobacco.

Friday, 15 July 2011

Reefer Madness - the evidence

Peter Hitchens asks: I want to know precisely which claims he [i.e. I, T.W.] views as ‘overblown’, and whether he accepts that cannabis has - or might in future be found to have - any dangers for those who use it. And if so, what he believes those dangers are..

I certainly do accept that cannabis carries some risks and is implicated in some harmful outcomes.

Cannabis - harms and dangers

First, I've already mentioned that smoking cannabis carries a risk of cancer. It hardly need be added that I would assume it imposes the other major risks associated with smoking. [UPDATE 17 Jul 2011 18:50: But see following post.] In any case, in Europe cannabis is most commonly smoked mixed with tobacco (and unfiltered, though that may be something of a red herring). So far as the present debate goes, Hitchens though has already said As for the risk of cancer, while it undoubtedly exists, it is not my principal concern..

Second, there are the effects of intoxication, some of which may be unwelcome. While stoned, for example, users tend not to be very attentive to some things, and may fail to lay them down in their memory - this is the fabled 'short-term memory loss'.

A stoned person may become rather self-absorbed and 'self-conscious' - that is, conscious of themself as the object of others' attention. This can mean not only being oversensitive to actual attention (yes, those 12 year old girls at the back of the bus might well be giggling about you, that shopkeeper might well be looking at you funny - but normally you wouldn't even notice, let alone care), but also 'paranoid' or oversuspicious of others.

In cases of extreme intoxication - for example after ingesting relatively large quantities of hashish (cannabis resin) - it is even possible to experience hallucinations.

Stoned folk often become lazy and may spend an inordinate amount of time arguing about who is going to go to the 24-hour garage to get Twixes and chocolate-flavoured long-life milk. Some people find the whole thing distinctly unpleasant, and may even in some circumstances feel sick - in which case once the effect has largely worn off in an hour or so, they can give it a miss and do something else. But all of these effects are transient, that is they do not persist once the drug is out of the user's system.

Third, problematic patterns of usage. I have no doubt that just like a hundred other activities, from overeating to computer games to routine and joyless sexual activity, cannabis can become the focus of obsessive and excessive behaviour. Being very stoned all the time is, just to be clear, not a good way of going about things. It is not going to do one's state of mind any good. Distancing oneself from reality for a prolonged period is bound to end up distorting your view of the world, your relationships and even to cause such warped perceptions and habits of mind as to count, technically, as 'psychotic symptoms' (this covers much more than persistently hearing voices, or harbouring bizarre and grandiose delusions). But such symptoms are symptoms of cannabis use or of an ongoing cannabis 'dependency', not of anything else.

Cannabis can no doubt be used as a crutch to deal with problems which would be better faced up to. (Or in some cases, perhaps for problems which are not best faced up to - in this vale of tears, we've all got to try and muddle through somehow and if you can fend off misery for a while I'm not going to frogmarch you off to the cells for it).