New PsychoactIve Substances - Evidence Review

This paper summarises the key information currently available on New Psychoactive Substances (NPS) and evidence gaps. Data on Scotland is presented in the context of UK and international evidence.

Executive Summary


This paper summarises key information on New Psychoactive Substances (NPS) and evidence gaps. Data on Scotland is presented in the context of UK and international evidence.

Definition of NPS

In the UK, the Advisory Council on the Misuse of Drugs (ACMD) defines 'new psychoactive substances' as: "psychoactive drugs which are not prohibited by the United Nations Single Convention on Narcotic Drugs or by the Misuse of Drugs Act 1971, and which people are seeking for intoxicant use". Although not scheduled under the UN drug control conventions, a number of the NPS mentioned in this paper are now controlled in the UK (e.g. mephedrone, BZP, NBOMe and Benzofury).

Main types of NPS available

The number of NPS available is constantly changing and growing which makes it difficult to identify levels and risks of use and for health and enforcement agencies to respond. NPS can contain legal substances, illegal substances, or even a mixture of both. They can be grouped according to their chemical names, or more usefully, by their intended effects on the user (e.g. stimulants). A record number of 81 substances were detected for the first time in Europe in 2013, up from 73 substances in 2012, 49 in 2011, 41 in 2010, and 24 in 2009 (EMCDDA, 2014). However, this increase in numbers should be treated with caution, given that it may in part reflect increasing efforts and capability to detect NPS, and that most of these drugs have not been seen in the UK.

Prevalence of use

Evidence from national surveys shows that use of NPS amongst the general adult population (e.g. those aged 16-59) is relatively low compared with use of other illicit drugs. However, use amongst younger age groups and some sub-sections of the population is higher. This pattern also applies in Scotland, where mephedrone is the most common NPS, used by 1.6% of all 16-24 year olds in the last year, but by only 0.4% of all adults. Cannabis is still the most commonly used illicit drug in Scotland, taken by 5.1% of all adults in the last year (2012/13 Scottish Crime and Justice Survey).


In Scotland, there were 213 seizures of NPS (mephedrone and ketamine) by police forces in 2012/13[1]. This was around 1% of the overall number of Class B and C drug seizures in Scotland. NPS have been seized in most countries across the world, but there are regional variations. Most NPS originate from Asia, followed by Europe, the Americas, Africa and Oceania. The internet plays an important role in the supply of NPS, with 651 internet shops identified in Europe in 2013 (EMCDDA, 2014).

Health implications

Evidence is limited, but indications are that NPS can cause a range of physical and psychological symptoms (from kidney failure to psychosis) that are just as serious as for other illicit drugs and can even result in death. In Scotland, over the five years from 2009 (when the first figures became available) to 2013, NPS have been implicated in 132 deaths (less than 5% of the total number of drug related deaths over that period) and in 18 of these an NPS was the only drug implicated (less than 1% of the total number of drug related deaths). Drug treatment services in the UK are seeing increased presentations from people using NPS, and reports of problems related to their use.


Countries are responding to the growth in demand and supply of NPS, and associated harms, in three main ways: enforcement (i.e. through legal controls); prevention (i.e. trying to stop people taking them in the first place); and treatment (for those experiencing problems from taking NPS).

A range of different actions can be taken to place NPS under legal control. These include: adding new substances to the 1961 or 1971 UN Conventions; using the European Early Warning System (EWS) to identify NPS and place them under control; and various national measures which involve using consumer safety or medicines legislation, extending and adapting existing laws and processes, or devising new legislation for new substances. In the UK, the government has control of substances under the Misuse of Drugs Act 1971. If a drug is causing sufficient concern, the UK Government (following consultation with the Advisory Council on the Misuse of Drugs (ACMD)) can issue a Temporary Class Drugs Order for up to 12 months. The ACMD then has 12 months to investigate and recommend classification if they consider there is sufficient evidence. Although these measures may have worked to some degree in individual countries, they have left loopholes in the global control system which can be exploited by drug manufacturers.

Efforts are also now being made to reduce the demand for NPS by educating young people and implementing targeted prevention initiatives. For example, in Scotland information on NPS is provided on the Know the Score website and to school children through the Choices for Life initiative.

To date treatment for NPS users who seek formal help is primarily supportive and there is limited information on what constitutes appropriate psychosocial treatment for this group.

Evidence gaps

The following are needed in order to inform future policy responses to NPS (both in Scotland and more widely):

  • A full assessment of what is known about the scale and patterns of NPS use.
  • Exploration of the nature of the relationship between the new drugs market and the established market in controlled drugs.
  • An examination of the short and longer term health impacts of using NPS, and other outcomes.
  • A systematic review of the outcomes of the various control systems.
  • Analysis of how current interventions to prevent substance misuse and harms may be used for NPS, and consideration of possible new approaches.
  • Evidence of what constitutes appropriate psychosocial treatment for NPS users.


Email: Fiona Fraser

Back to top