New PsychoactIve Substances - Evidence Review

3 Prevalence Of Use

Key Findings

• Evidence from national surveys show that use of NPS amongst the general adult population tends to be relatively low compared with use of other illicit drugs.
• However, use amongst younger age groups and some sub-sections of the population - e.g. regular night clubbers - may be higher.
• This pattern also applies in Scotland, where mephedrone was the most common NPS, used by 1.6% of all 16-24 year olds in the last year, but by only 0.4% of the general adult population (16-59).
• Cannabis is still the most commonly used illicit drug in Scotland, taken by 5.1% of all adults in the last year.

Use in the general population

3.1 There are no global estimates of the prevalence of use of NPS in the general population, only limited data from a few countries on specific substances and sub-populations. Several countries have included NPS in their national drug surveys (e.g. Australia, Canada, New Zealand, USA, the UK), but many have limitations including: lack of common definitions and of representative samples; the large and increasing number of substances regarded as NPS; and differences in legislation between countries. Evidence from the few surveys that cover the general population suggest that levels of NPS use in the general population are generally low. In the UK, our most robust estimates of NPS use in the general population come from our national crime surveys.

3.2 In Scotland, the 2012/13 Scottish Crime and Justice Survey reported that 0.5% of all adults had tried any NPS in the last year (Scottish Government, 2014). Mephedrone was the most commonly taken NPS, tried by 0.4% of all respondents in the last year. This compares with 1.7% for cocaine and 1.3% for ecstasy. Cannabis is still the most commonly used illicit drug in Scotland, taken by 5.1% of all adults in the last year.

3.3 In England and Wales the 2013/14 Crime Survey (Home Office, 2014) found that, of adults aged 16-59, 0.6% had taken mephedrone in the last year, 2.3% had taken nitrous oxide in the last year and 0.5% had taken salvia in the last year. This compares with 2.4% for cocaine 1.6% for ecstasy. Cannabis is still the most commonly used illicit drug in England and Wales, taken by 6.6% of adults in the last year.

3.4 In Northern Ireland, the Drug Prevalence Survey (DPS) 2010/11 found last year prevalence of NPS to be 3.5% (NACD, 2012). Again, Cannabis is the most commonly used illicit drug in Northern Ireland, taken by 5.1% of adults in the last year.

Use amongst younger age groups

3.5 Despite use of NPS in the general population being relatively low, surveys have found that use in the younger age groups can be considerably higher than in other areas of the population. This is presumably why many surveys only ask about prevalence of NPS use in younger age groups. For instance, the Eurobarometer Survey (European Commission, 2011) surveyed the experiences and attitudes of young people (aged 15-24) in Europe towards legal and illegal substances in 2002, 2004, 2008 and 2011 (UNODC, 2013a). Evidence from these surveys of young people also reveal regional variations in levels and types of NPS use.

3.6 Use of NPS by young people in 2011 appeared to be highest in the USA, where it was estimated that around 10% of those aged 15-25 had experimented with NPS, compared with around 5% in Europe^[4]. Again, in the UK our national crime surveys currently provide the most robust measure of prevalence in younger age groups.

3.7 In Scotland, the 2012/13 Scottish Crime and Justice Survey reported that 2.1% of those aged 16-24 had used any NPS in the last year and last year use of mephedrone (the most commonly used NPS) amongst 16 to 24 year olds was 1.6% (Scottish Government, 2014). The Scottish Schools Adolescent Lifestyle and Substance Use Survey (SALSUS)^[5] (Scottish Government, 2011) found that the use of any NPS by 13 and 15 year olds was uncommon (<1%) and 2% of 15 year olds said they had used mephedrone in the last year. Results from 2013 SALSUS will be available in November 2014.

3.8 The England and Wales Crime Survey found that in 2010/11, last year use of mephedrone (the most commonly used NPS at that time) amongst 16 to 24 year olds was 4.4% - the same level as the second most commonly used drug, cocaine powder. However, by 2013/14 this had fallen to 1.9%. Also in 2013/14, 7.6% of 16-24 year olds had taken nitrous oxide in the last year, and 1.8% had taken salvia.

3.9 In Northern Ireland in 2010/11, last year use of mephedrone and 'legal highs' was 2.2% and 2% respectively amongst adults aged 15-34 (NACD, 2012).

Use among specific groups of the population

3.10 As well as general population surveys, attempts have been made to measure the use of NPS amongst certain sub-groups of the population, such as night clubbers. In such populations the use of NPS can be very high and such studies provide insights into the harms a drug may have and the potential for new drugs to become more widespread (EMCDDA (2013b).

3.11 In late 2013, over 7,000^[6] people from the UK responded to the annual Global Drug Survey. The self-nominating sample were typically in their in 20s and 30s, well-educated, and about 50% went clubbing at least 4 times a year. Some key findings are:

• Synthetic cannabinoids, remained the most commonly used new psychoactive drug (last year use) across the sample.
• Among regular clubbers in the UK as a whole, mephedrone use in the last year fell from 13.8% in 2012, to 12.5% in 2013 (in Scotland, mephedrone didn't make it into the list of top 20 drugs, based on 631 responses).
• Ketamine use in the last year also fell, from 31.5% in 2012 to 19.8% in 2013 (14.7% in Scotland, based on 631 responses).
• In 2013, nitrous oxide was used by 20.4% UK respondents (10% in Scotland, based on 631 responses) in the last 12 months, compared with 27% in 2012.
• In 2013, 10.9% of all UK survey respondents had taken a mystery white powder in the last year (9.3% in Scotland, based on 631 responses) with almost 80% stating that they were already intoxicated before taking it.

(Winstock, A., 2014)

3.12 The latest in a series of surveys in 'gay friendly' nightclubs in South-East London (Wood, Hunter, Measham and Darghan, 2012) collected data on use of a wide range of NPS via a questionnaire survey. In July 2011, customers were asked about life-time use, last month use and/or use on the night of the survey/planned use later that night of NPS, cocaine and MDMA/ecstasy. A total of 313 individuals were surveyed over 4 nights; 206 (65.8%) had previously used a 'legal high'. Mephedrone had the highest prevalence of last month use (53.2%) and use on the night of the survey (41.0%). This was greater than both cocaine (44.6% and 16.7%, respectively) and MDMA/ecstasy (26.9% and 5.8%). There was limited 'on the night' use of the non-mephedrone 'legal highs': methoxetamine (1.6%) and 1-benzylpiperazine (0.6%), Spice/K2 (0.6%) and pipradrols (0.6%).The study concluded that although a significant proportion of individuals reported use of NPS, only mephedrone had become an established part of the recreational drug scene.

Use amongst those presenting for specialist drug treatment

3.13 Data from drug treatment services can also provide an indication of levels of use of certain substances and the extent to which they are causing problems for people using them. So far, treatment data on NPS is almost non-existent, but some countries have started to collect data. For instance, in England and Wales, the National Treatment Agency (NTA) has started to collect treatment data on ketamine, mephedrone, methamphetamine and GHB. The USA also reports on the number of visits to emergency departments that specifically involved synthetic cannabinoids (11,406 in 2010) (UNODC, 2013a).

3.14 In Scotland, among individuals attending drug treatment services, presentations by people using mephedrone (only been captured by treatment statistics in the last 2 years) are small in number. In 2011/12, 1.4% (111 individuals) of those reporting illicit drug use in the past month, reported using it at initial assessment with 35 of these reporting it as their main drug. This is down from 2010/11 where 1.6% (133 individuals) reported using Mephedrone, with 69 of these reporting it as their main drug (ISD, 2013).

3.15 Presentations at drug treatment services in England by people using mephedrone, methamphetamine, ketamine, and GHB have increased in recent years (Public Health England, 2013b). The National Treatment Agency (NTA) reports that, while overall drug use has fallen, the number of people needing treatment for club drugs has risen. Club drug users now make up 2% of over 18s and 10% of under 18s in treatment^[7]. As many as 1 million people may use club drugs. The NTA warns that the delay between people using a club drug for the first time and developing a dependency could mean that treatment figures continue to rise (National Treatment Agency, 2012).

3.16 Stakeholders in Wales have also reported a rise in referrals related to mephedrone and an increase in its use in conjunction with other substances (Welsh Government, 2013). In Wales during 2010/11, 88 people accessed treatment for mephedrone use with an average age of 21 years (Public Health England, 2013a).