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Pontifications on Poison

Being some ramblings on events associated with poisonous plants.

Thursday 28th July 2011

Two reports, published on the same day look at substance use in England and Wales. The British Crime Survey (BCS) has, for some years, undertaken a separate survey of illegal substance use in 16 to 59-year olds. The reason for the age range is that illegal substance use for over 60s is perceived to be too low to produce meaningful survey data and the under 16s are dealt with by the second report.

This second report is prepared by the NHS and covers England only but does include smoking and alcohol as well as classified substances. Both reports can be downloaded as pdfs. The BCS report, ‘Drug Misuse Declared’, is available via the Home Office website and the NHS report on young people is directly available here.

Cannabis sativa

Cannabis sativa

I’ll start with the BCS report. The British Crime Survey was introduced to deal with the problem of unreported crimes and to assess people’s perception of the level of crime. The first survey was undertaken in 1982 and there were eight further surveys between then and 2001. In April 2001, the survey became a continuous operation with results being reported on a financial year basis. This, of course, can lead to problems because people surveyed in May one year may give different responses to those surveyed the following February especially if some high profile crime has been in the news. But, the BCS is thought to be a useful tool for spotting trends rather than a reliable measure of absolute crime levels.

And the same is true of the add-on drugs survey that was first introduced in 1996. The methodology of the survey is that the interviewer who conducts the BCS survey face-to-face asks the interviewee to participate in the drugs survey and then allows them to enter their responses directly into the interviewer’s computer which encrypts them to prevent access by the interviewer.

There are flaws to this method. The person submitting the data may simply lie, though the survey always includes a fictitious substance so that some of the most blatant liars are eliminated. It relies on recall, which may be faulty for all sorts of reasons and because it is conducted in households it misses those on the margins of society. Overall, it is believed that ‘Drug Misuse Declared’ underestimates both total use and more especially use of opiates such as heroin. The report, for example, estimates that no more than 53,000 people used heroin in the previous twelve months but that number is far fewer than the number of problem users who received treatment.

Erythroxylum coca, cocaine

Erythroxylum coca, cocaine

But, as with the main BCS, the results are thought to be consistently wrong year to year so that useful trend data can emerge. For 2010/11, the main survey results show nothing too remarkable in terms of trends. Overall, lifetime prevalence, at 8.8%, is unchanged since last year and, therefore, remains below 1996’s 11.1%. Class A substance use has changed very little over the period going from 2.7% in 1996 to 3.0% now but within that there has been a reduction in hallucinogens like LSD and an increase in powder cocaine. The year on year results suggest that interest in cocaine may have peaked because it is the only substance showing a statistically significant decline in last year prevalence for 2009/10 to 2010/11.

The main change, in the long-term trend, is the continued fall in popularity of cannabis, though it remains by far the most used of all the classified substances. This downward trend applies to all 16-59-year olds and to the 16-24-year old subset and appears to have been unaffected by both the downward classification to Class C and its subsequent return to Class B.

And that is the main finding of this survey; that legal status doesn’t seem to have any bearing on substance use. For the first time, this year, the survey contained questions about mephedrone. When the media first showed an interest in mephedrone, it was widely suggested that its legal status was encouraging new users who either associated ‘legal’ with ‘safe’ or had respect for the law that prevented them from using classified substances.

Papaver somniferum, opium poppy

Papaver somniferum, opium poppy

‘Drug Misuse Declared’, as well as collecting prevalence data on mephedrone showing an annual prevalence of 1.4%, the same as ecstasy, for the whole age range and a 4.4% prevalence amongst 16-24-year olds, the same as powder cocaine, asked questions about other substance use for mephedrone users. This showed that 91% of mephedrone users had also used another classified substance in the preceding year. This suggests that mephedrone was an alternative favoured because of the unreliability of ecstasy, in particular. The idea that ending prohibition would lead to a huge increase in use because there is a large reservoir of people who want to take drugs but are deterred by the law appears not to be so.

Also for the first time, the survey asked about people’s attitudes to substance use. A disappointing 74% of adults say that getting drunk occasionally is acceptable though, thankfully, this falls to 6% who think frequent drunkenness is alright. Interestingly, though annual prevalence of cannabis use is only 8.8%, 33% of people surveyed thought its occasional use was acceptable.  Only 2% thought occasional heroin use was acceptable and 9% felt the same about cocaine. Because these were first time questions it is not possible to say if there is a trend towards finding cannabis use, at least, more acceptable. We’ll have to wait for future surveys to see that.

With the two surveys published on the same day there is a temptation to take the NHS 11-15-year olds’ data and try and read it across to what happens when people reach adulthood. The surveys, however, are conducted in different ways and look at different substances so a direct read across should be avoided. For that reason, I’ll look at the situation for under 16s tomorrow.