Tuesday, September 30, 2008

Pot does NOT make young people depressed

The study does appear to cover heavy users of marijuana so the finding is a bit surprising. Heavy use does seem to promote paranoid psychosis to some degree but depression is apparently different. The possibility of long-term effects manifesting in later life remains, however. Abstract follows:

Adolescent Cannabis Problems and Young Adult Depression: Male-Female Stratified Propensity Score Analyses

By Valerie S. Harder et al.

Cannabis use and depression are two of the most prevalent conditions worldwide. Adolescent cannabis use is linked to depression in many studies, but the effects of adolescent cannabis involvement on young adult depression remain unclear and may differ for males versus females. In this cohort study of youth from a mid-Atlantic metropolitan area of the United States, repeated assessments from 1985 (at age 6 years) through 2002 (at age 21 years) were made for 1,494 individuals (55% female). Measured covariate differences between individuals with and without cannabis problems were controlled via propensity score techniques. The estimated risk of young adult depression for adolescents with cannabis problems was not significantly different from that for comparison adolescents for either females (odds ratio = 0.7, 95% confidence interval: 0.2, 2.3) or males (odds ratio = 1.7, 95% confidence interval: 0.8, 3.6). The evidence does not support a causal association linking adolescent-onset cannabis problems with young adult depression.

American Journal of Epidemiology 2008 168(6):592-601

The moralistic myth of the `demon drink'

The UK government's list of nine types of heavy drinker is based less on scientific research than puritan zeal. It's part of a campaign that is both absurd and insulting

Do you drink to `unwind and calm down and to gain a sense of control when switching between work and personal life'? Perhaps your preferred way to `reconnect with old friends' is to meet up in a pub. Maybe you drink in `fairly large social friendship groups' and find a `sense of community' in your local pub, or perhaps you don't go out, and just drink at the end of the day when all your chores are done.

If any of this applies to you, and if you're over 35, you'll soon be targeted by a UK government health campaign, which, according to public health minister Dawn Primarolo, will help people `understand the effects of their drinking habits and help them make changes for the better'.

Underlying this forthcoming campaign is new research by the Department of Health (DoH) which has defined nine personality types of `heavy drinkers', that is, men who drink over 50 units of alcohol a week, and women who drink over 35 units a week. These types not only include `depressed drinkers' and `border dependents', which might well indicate potentially serious alcohol-related psychological problems, but `de-stress drinkers', `re-bonding drinkers', `community drinkers', `conformist drinkers', `macho drinkers', `boredom drinkers' and `hedonistic drinkers'. The DoH hopes to use this segmentation to, in the words of one report, `tailor its propaganda to suit all the target personalities' (1).

According to the report, alcohol serves many functions: it's the `shared connector' that helps people to get along with old friends; it's the means to `feel a strong sense of belonging and acceptance' or a `sense of community' at the local pub; it's the tipple of an evening born of boredom; or it's a way to express `independence, freedom and "youthfulness"'. The net effect of the research is to transform normal behaviour like relaxing after work, socialising with your friends, or just relieving your inhibitions and having a good time, into pathological conditions dangerous to your health (2).

Yet, as with all governmental lifestyle regulation, the basis for the DoH campaign is moral and political, not scientific or medical (3). The cod-psychologising about `drinking types' aside, even the notion of a `heavy drinker' is suspect, based as it is on government-defined unit limits that have no scientific basis. A former editor of the British Medical Journal involved in the process of setting the government's recommended drinking limits, which were first introduced in 1987, recently revealed that reports advising that moderate drinking above these limits was beneficial to health were simply suppressed in favour of `useless' limits that were `plucked out of the air' (4).

Instead, the government seems intent on commissioning scientists to try to produce evidence to back up its essentially moralistic obsession with how much we drink. This July, for instance, research at the North West Public Health Observatory (NWPHO) fuelled suitably scary headlines, warning that 15,000 people die from alcohol-related deaths annually, a leap of 80 per cent on previous estimates. Alarmingly, over a quarter of all deaths among 16- to 24-year-olds were attributed to alcohol. On this basis the DoH stated alcohol-related hospital admissions totaled 810,000, costing $5bn a year (5). But on closer examination of the facts, the continued politicisation of science becomes obvious:

* The NWPHO research identifies 47 conditions caused by alcohol - 34 of them `partially', like cancer, and accidents like falls. This is actually a reduction from the previous total of 53, which was determined by the Cabinet Office in 2003, and included various scientifically unsubstantiated conditions (6). Despite this, the government continues to use its own dodgy figures to estimate alcohol-related National Health Service (NHS) costs, thereby claiming an increase from o1.7billion to o2.7billion between 2003 and 2006/7 (7). Moreover, the government continues to peddle its preferred figures of 810,000 hospital admissions and `15-20,000 premature deaths' when the NWPHO report identified significantly lower figures: 459,982 admissions and under 15,000 deaths (8). When the facts don't fit, just use your own.

* The massive leap in alcohol-related deaths is almost entirely related to the inclusion of these `partially' caused conditions (10,283 deaths out of 14,982), for which the evidence is weak. Associated risk factors are drawn from two decade-old pieces of research and have no `confidence intervals' associated with them. In other words, we don't know how reliable these numbers are. Given that we are talking about a few dozen or hundred cases of some conditions, the risk could be statistically insignificant. Furthermore, these `partially' caused conditions are largely accounted for by `mental and behavioural disorders caused by alcohol'. While it is true that many mentally ill people have alcohol problems, it is far from obvious that they are mentally ill because they drink. However, the uncertainties and qualifications scientists are compelled to indicate tend to be ignored in media commentaries and government statements. When in doubt, obliterate doubt.

* Even if we accept the figures as given, when put into context, they look far less scary. While 14,982 deaths sounds a lot, it constitutes just 3.1 per cent of deaths in the UK. Booze accounts for over a quarter of deaths among 16- to 24-year-olds, but in absolute terms this meant just 446 people in 2005; the percentage is high for the simple reason that very few people die young. Again, 459,842 hospital admissions sounds a lot, but it constitutes just 2.3 per cent of all hospital inpatient and outpatient admissions (9). Given that 70 per cent of Britons drink, these figures suggest a generally low health risk, with serious problems being confined to a hard-core minority. Despite popular belief that Britain has a serious drinking problem, the international figure for alcohol-related diseases is four per cent.

* The NWPHO report even admits that drinking seems to help prevent some conditions like heart disease, and initially its authors found drinking even saved 8,838 lives in 2005 - though they subsequently try to scale this figure back, selectively using research that found little preventive benefit, rather than the opposite (10). Still, if the context dilutes the message, dilute the context.

* The NWPHO research actually finds little evidence to substantiate the government's obsession with `heavy drinkers' beyond re-telling the already-obvious: that sustained alcohol abuse increases the risk of diseases directly caused by alcohol, like cirrhosis of the liver, alcohol poisoning and throat diseases. For some `partially' caused conditions, the evidence is very weak. The research actually finds that the incidence of cancer, hypertension and pancreatitis do not vary with alcohol consumption among men, and are in fact `attributable more to lower levels of alcohol consumption' among women. Instead of therefore questioning the link between boozing and such diseases, the report `suggest[s] that there is a requirement for harm reduction strategies to target the general population, and not just high-risk drinkers'. A failure to find the link is thus transformed into regulation for the entire population, on the basis of three diseases that account for a mere 0.07 per cent of annual hospital admissions (11).

Such contortions illustrate that scientific research is being harnessed to a pre-existing policy agenda that is rooted not in hard medical fact but in moral concerns. Put simply, elites have a moral problem with people who enjoy drinking. They describe town centres as `no-go areas', express amazement and disgust at the revelation that 5.9million of us `drink to get drunk', and hope 24-hour licensing laws will moderate our barbaric customs in the direction of `European caf, culture'. This contempt for the masses, coupled with the vacuousness of their own visions for how to take society forward, produces moralising and therapeutic interventions designed to wean us from the bottle.

The DoH suggests heavy drinkers booze because of a `general sense of malaise in their lives' and to `give their lives meaning'. Perhaps they do. But is it really the state's place to psychoanalyse us, pathologise our normal social interactions, and scare us into `making changes for the better'? After the smoking ban left them without a focus for public health policy, it's actually health ministers who experienced a `general sense of malaise' and now resort to hectoring drinkers to `give their lives meaning'.

So if you receive one of the 900,000 leaflets and self-help booklets being targeted at heavy drinkers in the next few weeks, do the rational thing: bin it, and tell the `health promotion' lobby that really should get out more.


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