What are New Psychoactive Substances?

New psychoactive substances (NPS) are drugs designed or introduced to produce effects similar to established controlled substances. They may act as stimulants, sedatives, hallucinogens or cannabinoids, but their contents and strength can be unpredictable.

These substances were once widely described as “legal highs”. That term is now misleading. The Psychoactive Substances Act 2016 made it an offence in the UK to produce, supply, offer to supply, import or export psychoactive substances intended for human consumption, subject to specified exemptions. Some NPS are also controlled under the Misuse of Drugs Act 1971.

Important: A substance being sold online or in branded packaging does not mean it is legal, tested or safe. If someone is seriously unwell after taking a drug, call 999 immediately.

Contents

• The Emergence of New Psychoactive Substances
• New Psychoactive Substance Use
• Health Harms
• Why Are New Psychoactive Substances Produced?
• How Are These Substances Used?
• What Are the Risks of NPS?
• How Many NPS Are There?
• What Is the Legal Situation?
• What About Drug Testing?
• What to Do in an Emergency

The Emergence of New Psychoactive Substances

NPS became increasingly visible in the UK during the 2000s and 2010s. Manufacturers could alter a drug’s chemical structure to create a new compound while attempting to avoid controls that applied to an existing substance. Products were sometimes sold as incense, plant food, research chemicals or bath salts and marked “not for human consumption”. These labels did not make them safe.

The word “new” does not necessarily mean that a substance was recently invented. It can mean that it has only recently appeared on the recreational drug market or come to the attention of monitoring organisations. The United Nations Office on Drugs and Crime operates an early warning system that monitors NPS reported around the world.

New Psychoactive Substance Use

NPS include several broad groups. Examples include synthetic cannabinoids commonly associated with names such as Spice, synthetic cathinones with stimulant effects, dissociatives, sedatives and synthetic opioids. Nitazenes are a particularly concerning group of potent synthetic opioids that have been linked to overdoses and deaths.

The market changes quickly. A familiar product name or appearance does not guarantee that two samples contain the same compounds or dose. A product may contain a different drug from the one advertised, a mixture of substances, or unexpectedly potent ingredients.

Health Harms

The effects depend on the substance, dose, route of administration, other drugs taken and the person’s health. Possible harms include anxiety, agitation, confusion, hallucinations, seizures, overheating, chest pain, breathing difficulties, loss of consciousness and overdose.

Synthetic cannabinoids can cause severe anxiety, psychosis, seizures and cardiovascular problems. Stimulant-type NPS may increase heart rate, blood pressure and body temperature. Synthetic opioids can suppress breathing, and their potency may make very small quantities dangerous.

Mixing an NPS with alcohol, medicines or other drugs can make the effects less predictable and increase the risk of serious harm. Repeated use may also lead to dependence and withdrawal.

Why Are New Psychoactive Substances Produced?

Some are produced to imitate the effects of controlled drugs, to avoid detection by existing tests or to exploit gaps in drug controls. Others originate in legitimate pharmaceutical or scientific research before appearing in the illicit market.

As laws and testing methods change, suppliers may replace one compound with another. This constant change makes reliable identification, risk assessment and treatment more difficult.

How Are These Substances Used?

NPS may be sold as powders, tablets, capsules, liquids, herbal material, blotter paper or vaping products. Depending on the product, they may be swallowed, smoked, inhaled, snorted or injected. Injecting carries additional risks, including vein damage and transmission of blood-borne viruses when equipment is shared.

The appearance of a product does not reliably identify its contents. Packaging, colour, smell and branding can all be copied or changed.

What Are the Risks of NPS?

The main difficulty is uncertainty. There may be little reliable information about a newly encountered compound, including its effective dose, interactions, short-term toxicity and long-term effects. Even when the drug is known, the amount present may vary greatly between batches.

People can reduce immediate risks by avoiding mixtures, not using alone and starting with a much smaller amount than they might use of a more familiar substance. These steps cannot make an unknown drug safe. Anyone who experiences severe or unexpected symptoms should seek urgent medical help.

How Many NPS Are There?

There is no single fixed total because new compounds continue to appear and definitions differ between legal and monitoring systems. The UNODC Early Warning Advisory records substances reported by countries and territories worldwide, making it more useful than an easily outdated headline number.

What Is the Legal Situation?

Under the Psychoactive Substances Act 2016, it is an offence to produce, supply, offer to supply, import or export a psychoactive substance intended for human consumption. Possession with intent to supply and possession in a custodial institution are also offences. The Act contains exemptions, including alcohol, tobacco, nicotine, caffeine, food and medicinal products.

Some substances are separately controlled under the Misuse of Drugs Act 1971. In those cases, possession may also be an offence and penalties depend on the drug’s classification and circumstances. Because a product’s label may not accurately describe its contents, it can be difficult for a buyer to know which controls apply.

What About Drug Testing?

A drug test only detects the substances or metabolites included in that particular test. Standard drug-testing panels do not automatically detect every NPS, and a synthetic cannabinoid test cannot identify every compound sold as Spice. Always check the test’s stated targets, specimen type, cut-off levels and detection window.

Screening tests provide a preliminary result. They do not establish impairment, prove the quantity taken or guarantee the identity and purity of a substance. Where a result could affect medical treatment, employment or legal proceedings, an appropriate laboratory confirmation test should be considered.

What to Do in an Emergency

Call 999 if someone has difficulty breathing, loses consciousness, has a seizure, develops severe chest pain, becomes dangerously hot or shows any other serious or rapidly worsening symptoms. Tell the emergency team what may have been taken and keep any packaging if it is safe to do so. Do not leave the person alone.

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