Information on New Psychoactive Substances



‘Legal Highs’, New Psychoactive Substances (NPS)


What are they?


Basically, NPS are new drugs that mimic the effects of established illegal drugs such as cannabis, cocaine and ecstasy. Until recently* they could technically be sold or possessed legally. They come in many forms – as powders, pills, capsules, liquids and herbal matter sprayed with chemicals -and their names and effects are just as varied. In recent years many of these substances have been sold openly in bright and attractive packaging.  Regardless of their current legal status, these drugs have one thing in common – very little is known about them, their long term effects or the potential risks to physical and mental health.

Some substances sold as legal highs in the past have since been associated with health problems and even death. As a result, some ‘legal highs’ were subsequently banned under the Misuse of Drugs Act (mephedrone for example is now a class B controlled drug).


“The advent of novel psychoactive substances has changed the face of the drug scene remarkably and with rapidity. The range of substances now available, their lack of consistency and the potential harms users are exposed to are now complex and multi-faceted…” (ACMD 2011)



As with other established substances, new drugs can be broadly divided into three main categories, i.e.


DEPRESSANTS (depress the central nervous system e.g. heroin, alcohol, valium)

STIMULANTS (stimulate the central nervous system e.g. cocaine, amphetamine)

HALLUCINOGENS (alter perception, e.g. LSD, magic mushrooms, Ketamine).


These are however general, over-arching categories and there are many variations of potency and associated risks regarding individual substances.

New drugs vary in potency and there is no connection between strength and legal or previously legal status. They are no less risky than the better documented drugs – in fact they are probably more risky because so little is known about them.

Anyone buying these drugs cannot be sure what they‘re getting and the sellers’ main motivation is simply to get people to buy more.


 Legal highs: Marketed in bright and attractive packaging. Sold openly in head shops and online. Aimed at recreational users.

  • Research chemicals: Sold under the guise of being used for scientific research. Aimed at ‘psychonauts’ who explore the effects of psychoactive substances. Sold openly online.
  • Food supplements: Sold under the guise of being food or dietary supplements. Aimed at people wanting to enhance their body and mind. Sold openly in fitness shops and online.
  • Designer drugs: Passed off as drugs such as MDMA and heroin. Produced in clandestine labs by organised crime. Sold on illicit drug market by drug dealers.
  • Medicines: Medicines that are diverted from patients or illegally imported into Europe. Sold on illicit drug market by drug dealers.

 The emergence of the ‘legal highs’ and ‘research chemicals’ markets, which took off in the mid-2000s with the stimulants BZP and methylone (soon followed by mephedrone), was largely responsible for the dramatic growth in the market in recent years, and for catapulting new psychoactive substances onto the global policy agenda. Key to the success of both these markets was the fact that they were sold openly in specialised ‘head shops’ in towns and cities as well as via the Internet.

One of the largest groups of NPS is smoking mixtures that contain synthetic cannabinoids, which were intended as legal replacements to cannabis. These products were first popularised in Europe by the ‘Spice’ brand in the mid-2000s which were sold as herbal smoking mixtures under the guise of incense or room odorisers, but since then hundreds of different products such as ‘Black Mamba’, ‘Spice’ and ‘Chronic’ have been advertised and sold.


Mephedrone is a synthetic stimulant drug. It is chemically similar to the cathinone compounds found in the khat plant of eastern Africa. It comes in the form of tablets or a powder, which users can swallow, snort or inject, producing similar effects to MDMA, amphetamines and cocaine. Mephedrone was first synthesised in 1929, but did not become widely known until it was rediscovered in 2003. By 2007, mephedrone was reported to be available for sale on the internet, by 2008 law enforcement agencies had become aware of the compound and by 2010, and it had been reported in most of Europe, becoming particularly prevalent in the UK.

Between the summer of 2009 and March 2010, the use of mephedrone grew rapidly in the UK, with it becoming readily available at music festivals, head shops and on the internet. A survey of MixMag readers in 2009, found it was the fourth most popular street drug in the United Kingdom, behind cannabis and cocaine, and the drug was used by a diverse range of social groups. Whilst the evidence was anecdotal, researchers, charity workers, teachers and users reported widespread and increasing use of the drug in 2009. The drug’s rapid growth in popularity was believed to be related to both its availability and legality.

Criminologists believe the emergence of mephedrone was also related to the decreasing purity of ecstasy and cocaine on sale in the UK. Its low price was also attractive at a time of economic recession.

The increase in the use of mephedrone in 2009/10 and its widespread marketing across Europe was alarming, particularly for the rapidity with which the drug became first choice for users. Its detection and identification prompted its consideration by the Advisory Council on the Misuse of Drugs, who undertook an evaluation of the harms of the drug and concluded that it possessed similarities to existing pyschostimulants. Consequently, the ACMD advised the Government that it should be controlled, under the Act, as a Class B substance.



Overall, the growth in the market of new psychoactive substances has only been possible because of the growing interconnectedness of the world, driven by globalisation and the Internet. Many of the new psychoactive substances that are destined for these markets are produced in bulk by chemical companies based in China and India, and shipped to Europe by air freight, where they are processed, packaged and then sold to consumers.

Chemists are constantly using their knowledge to develop new recreational drugs and until recently they have tried to develop substances that are chemically similar to banned drugs but not governed by existing drug laws. There has been a huge demand for these drugs, not least because of their technically legal status,




 In the Queen’s Speech, on 27 May 2015, the government announced that:

new legislation will ban the new generation of psychoactive drugs.

The Psychoactive Substances Bill was introduced in the House of Lords on 28 May. The bill which will apply across the UK will:

“make it an offence to produce, supply, offer to supply, possess with intent to supply, import or export psychoactive substances; that is, any substance intended for human consumption that is capable of producing a psychoactive effect. The maximum sentence will be 7 years’ imprisonment”

There is no ban on possession of psychoactive substances except for possession of those drugs already banned and controlled under the Misuse of Drugs Act 1971 (such as heroin, cocaine, cannabis etc.) and unless there is ‘intent to supply’.

The bill will “exclude legitimate substances, such as food, alcohol, tobacco, nicotine, caffeine and medical products, from the scope of the offence, as well as controlled drugs, which will continue to be regulated by the Misuse of Drugs Act 1971”

So although alcohol, nicotine, caffeine and many other substances have or can be deemed to have a ‘psychoactive effect’ on people, the Government has stated that substances it considers to fall outside the scope of the new legislation will remain legal. Alcohol, nicotine and caffeine are specifically listed as exempt.

It was previously common for new drugs to be sold as ‘bath salts’, ‘plant food’, ‘incense’ or ‘research chemicals’ – the sellers labeled them in this way deliberately to avoid falling foul of the law on medicines (the Medicines Act) This is why they were also labeled ‘not for human consumption’.

None of these drugs were ever subjected to the strict testing procedures which are required before a new medicine for human use is granted a license.

‘Legal Highs’ have been sold openly in ‘Head Shops’ in the recent past but the new legislation will make it difficult if not impossible for proprietors to avoid prosecution and or closure of their premises.

The new Bill will:

“include provision for civil sanctions – prohibition notices, premises notices, prohibition orders and premises orders (breach of the two orders will be a criminal offence) – to enable the police and local authorities to adopt a graded response to the supply of NPS in appropriate cases”.

So it is likely this kind of open high street trade in NPS will soon be obsolete.

Owners and hosts of UK websites selling NPS and those buying from foreign sources are also liable to face prosecution for importing, exporting and supplying these drugs.

The proposed new legislation has been heavily criticised by experts in the drugs field, not least by the Government’s own advisors, the Advisory Council on the Misuse of Drugs [ACMD] – who incidentally were not consulted during the drafting of the new bill. The ACMD has said the Home Secretary’s bill introducing a blanket ban on “legal highs” risks “serious unintended consequences” and is unenforceable unless it is completely rewritten. Their concerns include:

  • The difficulty of proving the psychoactivity of a substance.
  • The criminalisation of young people who may buy substances for a group of friends (known as social supply) and related penalties which are disproportionate to the harms caused.
  • Medical and scientific research will be seriously inhibited by its terms because an exemption for clinical trials does not cover laboratory research in academia or industry.
  • The boosting of illegal networks due to the closure of ‘head shops’ leading to the possibility of users switching to more harmful substances.
  • The failure to distinguish between potentially harmful and harmless substances, which means suppliers of benign or beneficial substances could face prosecution under the bill.
  • The bill will have a substantial impact on the sale of many herbal medicines. Only a very small number of “registered traditional medicines” would be exempt from the bill.

The council has asked for talks with the home secretary over how to avoid the bill’s serious unintended consequences.



New Psychoactive Substances are new drugs that have emerged in recent years and those that continue to emerge onto a growing market. These drugs mimic the effects of established illegal drugs, but the chemists who produce them have altered their molecular structure so they fall outside of existing drug laws, thus making them technically legal. As such, they have been sold openly in head shops and via internet sites in recent years.

This situation is set to change however with the introduction of new UK wide legislation (The Psychoactive Substances Bill) which outlaws the sale, import and export of NPS (but not possession).

This legislation is currently in draft form and under debate in the House of Lords.

There appear to be serious flaws in the bill which could lead to unintended consequences and so far it has been heavily criticised by experts in the drugs field.

It seems likely therefore that the legislation as it currently stands will be amended if not rewritten.

NPS are likely to continue to pose major challenges to policy makers, law enforcement agencies and health care professionals in the next decade.

NPS present problems on a global scale including the further rapid production and trafficking of new substances. In response to new legislation, previously ‘legitimate’ suppliers may redirect stockpiles of a wide variety of potentially harmful substances onto an unregulated criminal market which will seek to exploit demand for these drugs. Users may be introduced to more powerful and dangerous substances via these criminal networks.