British Crime Survey nails young people’s use of mephedrone

For the first time, the 2010/11 sweep of the British Crime Survey (BCS) asked over 27,000 respondents from representatively-sampled households about whether they had used mephedrone in the past year. Nearly 3,700 of the BCS respondents in 2010/11 were aged 16-24 years.

The report, Drug Misuse Declared, prompted headlines in The Guardian and The Daily Mail this week which focused on mephedrone being now as popular among young people as cocaine. But that’s not the whole story,

The BCS finding was indeed that past-year use as reported by 16-24 year olds in 2010/11 was roughly the same for cocaine powder, mephedrone and ecstasy: 4.4 per cent for cocaine, 4.4 per cent for mephedrone, 3.8 per cent  for ecstasy. Please see Table below for approximate 95 per cent confidence intervals.

However, the Table also reveals equally important trends in past-year use of cocaine and ecstasy by 16-24 year olds. These are equally important because they were anticipated – at least by those who have read previous analyses of drug-taking on this website.

Specifically, on recent past performance from 2006/07 to 2009/10, we’d have expected around 7.0 per cent of 16-24 year olds in 2010/11 to have reported using cocaine in the past year. But only 4.4 per cent did. The decrease is highly statistically significant compared to both of the two preceding pairs of BCS sweeps.

This may have implications for cocaine-related deaths in 2009 and 2010 – particularly if cocaine use also decreased in older adults because users’ risk of cocaine-related death increases sharply with age. There are hints of such a decline in the table covering use by the age group 16-59 (see my second Table, below).

By comparison, the decrease in 2010/11 in young people’s reported use of ecstasy, itself a less lethal drug than cocaine, was more modest, and not statistically significant.

The extent and speed of mephedrone’s market penetration is apparent by comparison of its 2010/11 level with ketamine’s, about which BCS started to inquire in 2006/07. In 2010-11, 2.1 per cent of young people reported past-year use of ketamine (95 per cent CI: 1.6- 2.6 per cent), usage having been around 1 per cent in 2006/07+2008/09 but nearer 2 per cent since then, see first Table.

Compared to young people’s past-year use of cannabis in 2006/07+2007/08, there has since been a slight, but significant, decline in their use since then.

The back-story on mephedrone is as follows. Readers will recall that, on advice from the Advisory Council on the Misuse of Drugs (ACMD), legislation was passed on 16 April 2010 under UK’s Misuse of Drugs Act to control mephedrone as a class B substance.

The ACMD had received evidence that soldiers’ cocaine (and ecstasy) positive rate in compulsory drugs testing had decreased dramatically in 2009  - down from 4.8 in 2008 to 2.3 cocaine positives per 1,000 tests (based on around 90,000 and 100,000 tests respectively). In fact, the decrease was already evident in the last quarter of 2008.

The ACMD also had information from Mixmag’s opt-in survey in late 2009 that: 34 per cent of 2,200 self-selected respondents reported use in the past month of the then “legal high”mephedrone versus 47 per cent for cocaine and 48 per cent for ecstasy. It looked as if mephedrone had achieved some notable market penetration by 2009 with two-thirds as many respondents using mephedrone as using cocaine in the past month.

Unlike opt-in web-based surveys, however, BCS has a robust methodology that is consistent across years, and users representative sampling of households – although the number of young people sampled was reduced from the 2009/10 sweep to help fund BCS’s surveillance in the under 16s.

The question that BCS does not answer directly is this: for each of the five sweeps from 2006/07 to 2010/11, what proportion of 16-24 year old respondents reported past-year  use of “cocaine powder and/or ecstasy and/or mephedrone”. Clearly, only the 2010/11 sweep asked explicitly about mephedrone but if all three drugs share essentially the same market, then the answers have some relevance, and cannot be deduced from Drug Misuse Declared.

 

Conflict of interest: SMB writes in a personal capacity but is a member of Home Office’s Surveys, Design and Statistics Subcommittee.