Global use estimates
Regional use estimates
National use estimates
National treatment data estimates
Internet surveys on the use of new psychoactive substances
Global use estimates
The extent of global use of NPS remains unknown. Thus far, there are no estimates on the prevalence of use of NPS in the general population, but rather limited data collected in few countries, with respect to specific substances and sub-populations.
Concern about the increasing use of NPS and their potential adverse effects has led to a growing need for monitoring these substances and several countries have opted for the inclusion of NPS in national drug surveys. Some limitations of these surveys include the lack of common definitions and of representative samples, the large and increasing number of substances regarded as NPS, and the differences in legislation among countries.
Regional use estimates
In the framework of the European Union, the attitude of youth towards drugs is regularly examined by the Eurobarometer, which analyses public opinion in Member States of the European Union. Drug use surveys have been conducted among young people in EU Member States in 2002, 2004 and 2008 (Eurobarometer No. 172, 158, and 233). These surveys have studied the attitude of young people toward licit and illicit substances including heroin, cocaine, ecstasy, cannabis, alcohol and tobacco. In 2011, responding to recent developments in the EU drug market, the Eurobarometer “Youth attitudes on Drugs” (No. 330) asked young people for the first time about their experiences and attitudes towards new psychoactive substances or ‘legal highs’. For the purposes of the survey, NPS were understood as “a large number of new unregulated compounds that imitate the effects of illicit drugs (so-called new psychoactive substances or ‘legal highs’)”.
The sample size for the 2011 survey included over 12,000 randomly selected young people (aged 15-24) across the 27 EU Member States, who were interviewed by telephone. Youths were asked about their perceptions on the availability of NPS, perceived health risks associated to their use, attitudes towards banning or regulating NPS and about the effectiveness of alternative drug policies.
Overall, 5% of the participants reported having used NPS. Ireland (16%), Poland (9%), Latvia (8.8%) and the United Kingdom (8%), were at the higher end of the country ranking, while Italy (0.8%), Finland (1%) and Greece (1.6%) were found at the lower end. 
With respect to the supply of NPS, 54% of the respondents who had used NPS reported that they had been offered the substance by friends, 37% had been offered the substances during a party or in a club, 33% had purchased them from a specialized shop, and less than 7% had bought them over the Internet. Older respondents were more likely than their younger counterparts to have been offered such substances at a party or in a club (41% of 22-24 year-olds vs. 32% of 15-18 year olds), whereas those who had completed their higher education (41% vs. 27% among those who had only completed their primary education at the time of the survey) were more likely to have purchased the substances from a specialized shop.
Source: Flash Eurobarometer 330. Youth Attitudes on Drugs. Analytical report. May 2011.
Base: all respondents, % by country
Young people who reported having used NPS were also less likely to recognize the seriousness of the risks associated with regular and occasional use of various illicit and licit substances. Sixty percent of those who had never used NPS thought that using ecstasy occasionally posed a high risk to a person’s health and 26% saw a medium risk. By comparison, only 40% of those who had used NPS perceived the health risks caused by occasional ecstasy use as high, and 34% as medium. A similar pattern follows the perception of the risks associated to cannabis use.
With respect to responding to NPS, only 1% - 4% of the interviewees considered that no action was needed. However, preferences on whether to ban all NPS, to ban only those that pose serious risks to someone’s health or to regulate them, varied across EU Member States.
While there are some limitations of the results, including the small sample size in each State (in most EU countries the target sample size was 500 respondents, but in Estonia, Cyprus, Luxembourg, Malta and Slovenia the sample size was 250 respondents) to assess actual use and the lack of a common understanding on what constitutes a new psychoactive substance, the survey nevertheless provides a glimpse into the use of these substances by young people.
National use estimates
Apart from the above-mentioned regional estimates, national surveys in a general population and/or subpopulations have also been conducted in few countries to estimate the use of NPS. It should be noted, however, that often only a limited number of NPS (or even just a single one) is included in these estimates.
In Australia, information on the prevalence of use of NPS has been included since 2010 in the Drug Trends in Ecstasy and Related Drug Markets (EDRS) report. The 2011 report presents the most recent findings on the markets for ecstasy and related drugs based on data collected in all states and territories in Australia from surveys with regular ecstasy users, surveys with key experts who have contact with regular ecstasy users and the analysis of existing data sources that contain information on ecstasy and related drugs. Although the results from the regular ecstasy users surveys are not representative of ecstasy users and their other drug use in the general population, the data provided is indicative of patterns of drug use. In the 2011 EDRS survey, 574 regular ecstasy users were interviewed. Participants were recruited primarily through street press adverts and word-of-mouth.
According to the findings for 2011, ketamine use remained limited to Victoria, New South Wales and the Australian Capital Territory, with 16% of the national sample reporting recent use, a significant increase from 2010 (12%). A small proportion of regular ecstasy users reported the use of some NPS, for example, synthetic cannabinoids (‘spice’), synthetic cathinones (mephedrone, methylone, MDPV), phenethylamines (2C-I, 2C-E, 2,5-dimethoxy-4-iodoamphetamine (DOI)), piperazines (BZP), tryptamines and plant-based substances (datura). While in 2011, lifetime and recent use of ‘spice’ was low among the sample (1% and <1% respectively), five per cent of the national sample believed that they have used other form of synthetic cannabinoids.
Source: data from the 2011 EDRS report
Fields displayed as 0.00% indicate that data is not available
In 2011, ketamine, DMT (an internationally controlled substance) and mephedrone were the substances with the highest rate of lifetime prevalence. From 2010 to 2011, there was a significant decrease in recent use of mephedrone (16% vs. 14%). Regular ecstasy users reported in 2011 lifetime and recent use of methylone at 7% and 5%, while only a small number (2%) reported lifetime and recent use of MDPV in the same year. The use of phenethylamines showed significant increases in 2011; however the number reporting use remained low. Both lifetime (12%) and recent use (5%) of 2C-I (compared to 6% and 2% in 2010) increased as did lifetime (8%) and recent use (4%) of 2C-E (compared to 3% and 2% in 2010). Six per cent of the participants reported having tried a 2C-class drug (apart from those mentioned above) and thirty participants of the entire sample (5%) reported lifetime use of ‘other’ 2C-class drugs, including 2C-B-Fly, 2C-P, 2C-T-2, 2C-T-7. There was a decline in the number of users that reported recent use of BZP (2% vs. 4.5% in 2010). To a lesser extent, recent use of the plant based substance datura was reported by three of the participants (1%).
Source: data from the YSS 2010-11
In Canada, the use of NPS was recently included in the biennial ‘Youth Smoking Survey’ (YSS) conducted since 2002. The YSS helps schools and government agencies across Canada assess youth substances use and related health behaviours. The 2010-11 school-based survey included a representative sample of 50,949 (representing approximately 3 million youth) secondary school students from all provinces of Canada except New Brunswick. Survey results showed a higher last year prevalence of the use of NPS (salvia divinorum (3.4%), ketamine (1.6%), and ‘other illicit drugs’ (9.7%)) than for other illicit drugs, such as cocaine (2.3%) and heroin (1.1%). Cannabis remained the top illicit drug of choice (21.2%).
Questions on NPS were included for the first time in the Drug Prevalence Survey 2010/11 on drug use in Ireland and Northern Ireland. This survey included a sample of 7,669 people aged 15-64 (5,134 in Ireland and 2,535 in the United Kingdom (Northern Ireland)). In Ireland, NPS included ‘herbal smoking mixtures/incense, party pills or herbal highs, bath salts, plant feeders or other powders, kratom (krypton), salvia divinorum, magic mint, divine mint or sally D and other NPS mentioned by the respondent’, while in Northern Ireland, NPS (called ‘legal highs’) comprised ‘party pills, herbal highs, party powders, kratom and salvia divinorum’. Limitations of this survey include the lack of coverage of some groups with high drug use prevalence (e.g. the homeless, those in prison), refusal to participate in the survey or under-reporting of drug use, and, in some cases, the small sample size.
According to the 2010/11 results from the survey, lifetime and last year prevalence of NPS use in Northern Ireland were 2.4% and 1.0%, respectively. Both lifetime and last year use were higher among men (3.0%) than women (1.8%) and significantly higher for young adults (aged 15-34) than for older adults (aged 35-64) (4.8% vs. 0.6%). There was a separate question on the use of mephedrone in Northern Ireland and responses showed similar percentages of use to NPS in both lifetime (2.0% vs. 2.4%) and last year prevalence (1.1% vs. 1.0%). In Ireland, there is no data available on lifetime prevalence of NPS but last year prevalence among adults was 3.5%. Cannabis remains the most commonly used illicit drug in both Northern Ireland and in Ireland. However, in Ireland, after cannabis, NPS and cocaine (including crack) were the most frequently reported substances.
Source: data from the New Zealand Drug Use Survey 2007-2008
Base: all respondents %
In New Zealand, the most recent national survey data on the use of NPS is available from the New Zealand Drug Use Survey 2007/2008, which measured self-reported alcohol and drug use in the adult population. The survey collected information on 6,784 New Zealanders aged 16–64 years, including 1,825 Maori and 817 Pacific respondents. According to the results of this survey, lifetime and last year use of BZP (reported at 13.5% and at 5.6% respectively) was even higher than the use of amphetamines (7.2% and 2.1% respectively) or cocaine (3.6% and 0.6%). BZP users were significantly more likely to be male, aged between 18-34, and more likely to be Maori. Moreover, hospital discharge data corresponding to 37 people discharged for cases involving NPS between 2009-2011, showed that users of NPS were reportedly younger compared with people discharged for cannabis use, less likely to be Maori (41% compared to 51% of cannabis users) and less likely to be living in an area of high deprivation (27% compared to 40% for cannabis users). Prevalence of use of NPS approved under the legislation that is being drafted will be monitored through national surveys.
In the United Kingdom, new measures of drug use were added to the 2010/11 British Crime Survey (BCS), with the inclusion of drugs recently classified under the Misuse of Drugs Act. According to the findings from the 2010/11 survey, an estimated 8.8% of adults in England and Wales had used an illicit drug in the last year (almost 2.9 million people). Last year use of mephedrone (1.4 %) for adults aged 16-59, was at a similar level as ecstasy use (1.4%), the third most prevalent drug for this age group. For younger adults (aged 16-24), mephedrone use (4.4%) was at a similar level of use as cocaine (4.4%), the second most used drug in this age group. The use of synthetic cannabinoids, khat and BZP was only of 0.4%, 0.3%, and 0.2% respectively. Adults aged 16-24 showed higher rates of prevalence for both mephedrone (4.4%) and synthetic cannabinoids (0.4%) than adults aged 16-59 (0.6% and 0.1% respectively). Cannabis remained the most commonly used type of illicit drug with 6.8% of adults (aprox. 2.2. million people) having used this drug in the last year, followed by cocaine (2.1%, around 0.7 million adults) and ecstasy (1.4%, 0.5 million adults).
Source: data from the MTF Survey 2010-2011
Base: 12th graders %
Question on synthetic cannabinoids was introduced in 2011 for the first time
In the United States, the ‘Monitoring the Future’ survey has been conducted annually since 1975 to generate national data on drug use of American adolescents, college students and adults through the age of 50. In 2011, a question about the use of synthetic cannabinoids (‘spice’ and K2) was included for the first time in the survey, asking 12th graders about their use in the previous 12 months. The sample size of the 2011 survey encompassed about 46,700 secondary school students in 400 schools nationwide. According to the findings of the survey, synthetic cannabinoids ranked second only to natural cannabis in annual prevalence among 12th graders. Some 11.4% of 12th graders reported having used synthetic cannabinoids in the previous 12 months, while 5.9% of these users reported last year use of salvia divinorum. Overall, last-year use of NPS among 12th graders surpassed the use of other illicit drugs such as cocaine (2.9%) and heroin (0.80%) in 2011. Among all young adults aged 19-30, the annual prevalence of synthetic cannabinoids was 6.5%, but there were considerable differences by age. With annual prevalence rates in 2011 between 2% and 5%, salvia divinorum seems to be more widespread among 19-24 years olds than among those aged 25 to 30, where annual prevalence was less than 1%.
National treatment data estimates
Given their relatively recent emergence in the drug markets, treatment data on NPS is almost non-existent but some Governments have started to collect data on the impact of the use of NPS on public health systems.
In the United Kingdom, treatment data on ketamine and mephedrone were included for the first time in the 2012 report of the National Treatment Agency for Substances Misuse (NTA). The report showed that while the number of people entering treatment for ecstasy has halved from 2,138 in 2006-07 to 1,018 in 2011-12, ketamine and mephedrone cases have risen. Ketamine presentations continuously increased between 2005-06 and 2010-11, from 114 to 845, falling back to 751 in 2011-12. In 2012, 900 over-18s started treatment for mephedrone, compared to 839 in the previous year. The high numbers could indicate a potential strain on public health although it is not possible to predict long-term treatment demand on the basis of data for two years. In addition, many persons demanding treatment for NPS were relatively young. In 2011, 56% of all over-18s treated for mephedrone were aged 18-24.
The 2011 annual report of the National Programme on Substance Abuse Deaths (np-SAD) of the United Kingdom revealed an increase in the number and range of NPS identified in post mortem toxicology results and/ or as cause of death of cases notified to the Programme. NPS include para-methoxyamphetamine (PMA) (an internationally controlled substance), fluoroamphetamine (4-FA), tryptamines (5-MeO-DALT) as well as mephedrone, MDPV and naphyrone. The number of cases where mephedrone and MDPV were mentioned increased significantly in 2010: according to post mortem toxicology results, mephedrone rose to 46 reports (compared to 8 reports in 2009) and MDPV to 9 reports in 2010 (compared to 0 in 2009). Cause of death cases notified to the Programme also registered an increase in 2010 for both mephedrone (29) and MDPV (6) (compared to 5 and 0 cases in 2009, respectively).
In the United States, the first report on synthetic cannabinoids from the Drug Abuse Warning Network revealed that an estimated 11,406 visits of the approximately 2,300,000 emergency department visits that involved drug use in 2010 were specifically linked to synthetic cannabinoids. Three quarters of these emergency department visits involved patients aged 12 to 29 (75 percent or 8,557 visits), of which 78 percent were male, and in the majority (59 percent) of these cases, no other substances were involved. The average patient age for synthetic cannabinoids-related visits was 24 years, while it was 30 years for cannabis. Overall, synthetic cannabinoid-related visits were concentrated in the younger age groups: 75 percent of the visits involved patients aged 12 to 29, with 33 percent of the patients aged 12 to 17. In comparison, 58 percent of cannabis-related visits involved patients aged 12 to 29, with 12 percent in the 12 to 17 age group.
Internet surveys on the use of new psychoactive substances
Internet surveys have been conducted to assess the use of NPS. It should be noted that all known surveys on NPS have been conducted in Europe and that they are limited by the self-nominating nature of the sample and are therefore unrepresentative of the general population. The use of an online method of data collection implies that those who respond are likely to be more active online and that some populations with higher than average levels of drug use (e.g. the homeless and those in prison) as well as those with no access to the Internet are excluded.
In Germany, an online survey on use experiences and use patterns of various NPS was conducted in 2011. The survey was addressed to those with drug use experience and invitations to participate were extended to them via social networks, internet shops that offer legal highs, online forums on drug-related topics and prevention websites. The survey was completed online by 860 individuals (89% of the respondents were male and the average age was 24.2 years) from all over Germany. Reported lifetime prevalence of illegal drugs among the respondents was at 99%. Synthetic cannabinoids were reportedly the most prevalent new psychoactive substance, with a lifetime prevalence of 86%. Lifetime prevalence of research chemicals was at 39% and at 35% for ‘other legal highs’. More than half of the respondents reported having used at least one NPS in the last month. The users of synthetic cannabinoids were reportedly older on average and more frequently living in small towns. Current users of research chemicals were especially likely to be experienced and regular users of various illegal drugs. Overall, the respondents named more than 300 different substances which they had tried at least once. More than three out of five respondents indicated the legal availability of NPS as a major motivation for use.
In the United Kingdom, the British electronic dance and clubbing magazine ‘MixMag’ has conducted two surveys on NPS, in 2009 and 2011. The survey had been traditionally addressed to young club goers, but over the last few years it has attempted to involve a wider segment of the population. The first survey, carried out in 2009 (results were published in January 2010), collected data of lifetime, last year and last month drug use on 29 substances, including NPS such as synthetic cannabinoids, synthetic cathinones (MDPV, mephedrone, methylone), phenethylamines (2C-I, and 2C-T-7), piperazines (BZP), salvia divinorum and ‘other new psychoactive substances’. Although 3,500 responses had been received as of February 2010, the analysis here presented is based on a subset of 2,295 UK respondents, the majority of them aged between 18-27.
Source: data from the Mixmag Drug Survey, 2009.
The 2009 survey shows that lifetime and last-month prevalence of other NPS surpassed the use of illicit drugs such as heroin and methamphetamine. Last year prevalence showed ketamine as the most common new psychoactive substance (51%), followed by synthetic cathinones (mephedrone 37.3%), piperazines (BZP 12.1%), and, to a lesser extent, plant-based substances (salvia divinorum 8.9%) and synthetic cannabinoids (‘spice’ 6.2%).
Source: Source: data from the Mixmag Drug Survey, 2010.
It should be noted that samples for 2009 and 2010 are slightly different.
The second Mixmag survey was carried out in 2010, with results published in March 2011. More than 15,500 people worldwide took part in a similar Mix-Mag/the Guardian Drugs Survey, which makes it “the biggest ever survey of drug use among clubbers”, according to the organizers. Three quarters of the respondents were aged between 18-27 and two-thirds were male (69%). Two NPS were added to the 2010 survey; aminoindane derivative 5,6-methylenedioxy-2-aminoindane (MDAI) and phenethylamine derivative 6-APB (Benzofury). Although the results are not directly comparable from year to year as the composition of the sample is slightly altered, the 2010 survey findings showed a higher last year prevalence of mephedrone (51% in 2010 vs. 37% in 2009), and a fall in last year use of ketamine from 2009 to 2010 (50.7% vs. 41.2%). All in all, in 2010 last year use of several NPS such as synthetic cannabinoids (‘spice’) (2.2%), MDPV (3%), or BZP (5%) remained higher than last year use of drugs such as heroin (1.2%) and methamphetamine (1.0%).
The wording of the question was as follows: In certain countries some new substances that imitate the effects of illicit drugs are being sold as legal substances in the form of -for example -powders, tablets/pills or herbs. Have you ever used such substances? European Commission, Youth attitudes on drugs, Flash Eurobarometer 330, 2011, 18
 European Commission, ‘Youth attitudes on drugs’, Flash Eurobarometer 330, 2011 (http://ec.europa.eu/public_opinion/flash/fl_330_en.pdf)
 European Commission, ‘Youth attitudes on drugs’, Flash Eurobarometer 330, 2011 (http://ec.europa.eu/public_opinion/flash/fl_330_en.pdf)
 “The term ‘ecstasy and related drugs’ includes drugs that are routinely used in the context of entertainment venues and other recreational locations including nightclubs, dance parties, pubs and music (http://ndarc.med.unsw.edu.au/sites/ndarc.cms.med.unsw.edu.au/files/ndarc/resources/National_EDRS_2011%20final.pdf)
 Recent use in the EDRS report refers to prevalence of use in the past six months.
 Sindicich, N. and Burns L., ‘Australian trends in ecstasy and related drug markets 2011, findings from the ecstasy and related drugs reporting system (EDRS)’, Australian Drug Trends Series No.82, National Drug and Alcohol Research Centre, University of New South Wales, Sydney 2012 (http://ndarc.med.unsw.edu.au/sites/ndarc.cms.med.unsw.edu.au/files/ndarc/resources/National_EDRS_2011%20final.pdf)
Sindicich, N. and Burns L., ‘Australian trends in ecstasy and relateddrug markets 2011, findings from the ecstasy and related drugs reportingsystem (EDRS)’, Australian Drug Trends Series No.82, NationalDrug and Alcohol Research Centre, University of New SouthWales, Sydney 2012 (http://ndarc.med.unsw.edu.au/sites/ndarc.cms.med.unsw.edu.au/files/ndarc/resources/National_EDRS_2011%20final.pdf)
 Canada, Health Canada, ‘Summary of results of 2010-11 Youth Smoking Survey’, Controlled Substances and Tobacco Directorate, Waterloo, May 2012 (http://www.hc-sc.gc.ca/hc-ps/tobac-tabac/research-recherche/stat/_survey-sondage_2010-2011/result-eng.php)
 Other illicit drugs include, among others, hallucinogens (LSD, PCP, acid, magic mushrooms, mesc); ketamine (special k, kit-kat); GHB (G, liquid X, goop); Salvia (Divine Sage, Magic Mint, Sally D); Jimson weed (locoweed, stinkweed, mad apple). Canada, Health Canada, ‘Supplementary tables, Youth Smoking Survey 2010-11’, Controlled Substances and Tobacco Directorate (http://www.yss.uwaterloo.ca/results/YSS2010-2011_supplementary_tables_en.pdf )
 Canada, Health Canada,, ‘Supplementary tables, Youth Smoking Survey 2010-11’, Controlled Substances and Tobacco Directorate (http://www.yss.uwaterloo.ca/results/YSS2010-2011_supplementary_tables_en.pdf)
 Ireland and Northern Ireland (United Kingdom), National Advisory Committee on Drugs and Public Health Information and Research Branch, ‘Drug use in Ireland and Northern Ireland 2010/11: Drug Prevalence Survey: Regional Drug Task Force (Ireland) and Health and Social Care Trust (Northern Ireland) Results’, 2012
 New Zealand, Ministry of Health, ‘Drug use in New Zealand: key results of the 2007/08 New Zealand Alcohol and Drug Use Survey’, January 2010 (http://www.health.govt.nz/nz-health-statistics/national-collections-and-surveys/surveys/current-recent-surveys/alcohol-and-drug-use-survey)
 New Zealand, Ministry of Health, ‘Regulatory impact statement, new regulatory regime for psychoactive substances’, the Treasury, Wellington, July 2012 (http://www.treasury.govt.nz/publications/informationreleases/ris/pdfs/ris-moh-rrps-jul12.pdf)
 Development of the BCS questionnaire takes place on an annual basis and aims to reflect emerging issues. Questions about the use of ketamine were added to the BCS in 2006/07, questions about synthetic cannabinoids and benzylpiperazine (BZP) were added in October 2009, and questions about the use of mephedrone were added to the 2010/11 BCS questionnaire. Smith, K. and Flatley, J., ‘Drug misuse declared: findings from the 2010/11 British Crime Survey England and Wales’, Statistical Bulletin, United Kingdom Home Office, 2011
 In 2010, mephedrone was classified in the United Kingdom as a Class B substance under the Misuse of Drugs Act
 Smith, K. and Flatley, J., ‘Drug misuse declared: findings from the 2010/11 British Crime Survey England and Wales’, Statistical Bulletin, United Kingdom Home Office, 2011
 In the survey, synthetic cannabinoids were understood as a substance that “goes by such names as ‘Spice’ and K-2, and is an herbal drug mixture that usually contains designer chemicals that fall into the cannabinoid family”. Johnston, L. D., O’Malley, P.M., Bachman, J.G. and Schulenberg, J.E., ‘Monitoring the Future, national results on adolescent drug use, overview of key findings, 2011’, The University of Michigan, sponsored by The National Institute on Drug Abuse, National Institutes of Health, February 2012 (http://monitoringthefuture.org/pubs/monographs/mtf-overview2011.pdf)
 Johnston, L. D., O’Malley, P.M., Bachman, J.G. and Schulenberg, J.E., ‘Monitoring the Future, national results on adolescent drug use, overview of key findings, 2011’, The University of Michigan, sponsored by The National Institute on Drug Abuse, National Institutes of Health, February 2012 (http://monitoringthefuture.org/pubs/monographs/mtf-overview2011.pdf)
 National Treatment Agency for Substances Misuse, “Club drugs: emerging trends and risks”, 2012 (http://www.nta.nhs.uk/uploads/clubdrugsreport2012%5B0%5D.pdf ; accessed in: November 2012)
 United Kingdom, National Programme on Substance Abuse Deaths (np-SAD), ‘Drug-related deaths in the UK. Annual report 2011’, 2012
 United States, Drug Abuse Warning Network, ‘Drug-related Emergency Department visits involving synthetic cannabinoids’, 2012
 New psychoactive substances were broken down in herbal blends; other legal highs/bath salts; etc., and research chemicals. Werse, B. and Morgenstern, C., ‘Short report, Online survey on the topic of “legal highs”’, Centre for Drug Research, Goethe University, Frankfurt am Main, 2011
 Research chemicals refer to “new synthetic drugs that are (at least according to the declaration) sold in pure form under their actual chemical name. The generic term is independent of the activity profile and, in principle, it considers the whole spectrum of all the possible drug effects, even though there are focus areas. Research chemicals are, in some cases, labeled as “only for research purposes”. Werse, B. and Morgenstern, C., ‘Short report, online survey on the topic of “legal highs”’, Centre for Drug Research, Goethe University, Frankfurt am Main, 2011
 Other legal highs “includes all products except cannabis-like smoking blends, which are (mainly deliberately) wrongly labelled as “bath salts”, “air fresheners”, “plant food” etc. and contain synthetic psychoactive substances. It mostly includes drugs which have stimulant and entactogenic / empathogenic effects, and are therefore substitutes for popular party drugs’ such as amphetamine, ecstasy/ MDMA or cocaine”. Werse, B. and Morgenstern, C., ‘Short report, online survey on the topic of “legal highs”’, Centre for Drug Research, Goethe University, Frankfurt am Main, 2011
 Legal highs refer to synthetic cannabinoids; other legal highs/bath salts, etc., and research chemicals. Werse, B. and Morgenstern, C., ‘Short report, online survey on the topic of “legal highs”’, Centre for Drug Research, Goethe University, Frankfurt am Main, 2011
 Winstock, A., ‘Brief summary of the 2009/10 Mixmag’s survey (Winstock and Mitcheson) for the EMCCDA Annual report’, (http://ewsd.wiv-isp.be/Publications%20on%20new%20psychoactive%20substances/Mephedrone/Brief%20summary%20of%20the%202009-10_mixmag%20survey.pdf)