New psychoactive substances in homelessness services

New psychoactive substances (NPS) are synthetic (lab-made) chemicals designed to copy the effects of controlled drugs such as cannabis, opioids or stimulants.

They used to be known as 'legal highs'. That term is now misleading — all NPS are illegal in the UK, either under the Psychoactive Substances Act 2016 or the Misuse of Drugs Act 1971.

NPS are not one substance. They are a large and constantly changing group of chemicals. This makes them particularly dangerous: potency varies between batches, effects are unpredictable, and they are often mixed with other drugs without the user knowing.

Drug poisoning causes almost two in five deaths of homeless people in England and Wales. NPS are a growing part of that risk. Deaths linked to nitazenes — a synthetic opioid increasingly found in UK drug supplies — rose from 52 in 2023 to 195 in 2024.

NPS are not confined to rough sleeping. They are found in hostels, day centres, supported accommodation and outreach settings. People experiencing homelessness are more likely to use synthetic cannabinoids such as spice than the general population, and may be using other drugs that contain nitazenes without knowing it.

This means your service is likely to encounter NPS — if it has not already. This page covers what you need to know and what your service needs to have in place.

Synthetic cannabinoids (SCRAs)

Street names: Spice, Mamba, Black Mamba, K2, fake weed

These are designed to mimic cannabis but are much stronger and less predictable. They are usually smoked, and may look like dried herbs or be brightly coloured. They are increasingly found in vapes. They are common among people experiencing homelessness. Research in Manchester found users describing them as more addictive than heroin.

Signs and symptoms:

• Blank stare, slow or no response when spoken to
• Slurred or incoherent speech
• Vomiting
• Muscle spasms or unusual body movements
• Agitation, aggression or paranoia — effects vary widely and can change quickly
• Slumped, unresponsive or seemingly unconscious while still standing or seated — call 999 immediately

Synthetic opioids (nitazenes)

Nitazenes are lab-made opioids. Some are up to 500 times stronger than heroin. They are particularly dangerous because people often do not know they have taken them — nitazenes are increasingly mixed, without the user's knowledge, into heroin, cocaine, street benzos and fake pills.

Signs and symptoms:

• Drowsiness or difficulty staying awake
• Confusion or difficulty thinking clearly
• Nausea or vomiting
• Slurred speech
• Slow or shallow breathing
• Cold, clammy skin
• Loss of consciousness or inability to wake up — call 999 immediately

Synthetic cathinones

Street names: monkey dust, bath salts

These are stimulants that can cause severe agitation, paranoia and aggression. Most are Class B drugs. There has been particular concern about monkey dust in parts of England, with a government review published in February 2025.

Signs and symptoms:

• Extreme agitation or restlessness
• Paranoia or panic
• Aggression or unpredictable behaviour
• Sweating, grinding teeth
• Hallucinations — seeing or hearing things that are not there
• Unusual strength or apparent inability to feel pain

Novel benzodiazepines

Street names: benzos, blues, vallies

These are lab-made sedatives, similar in effect to diazepam (Valium), but not prescribed or licensed. They are often mixed into other street drugs without the user knowing.

Signs and symptoms:

• Drowsiness or sedation deeper than expected
• Slurred speech, confusion
• Loss of coordination or balance
• Memory loss — the person may not recall what happened
• Unresponsive but breathing — call 999 immediately

NPS are often cheaper and easier to get hold of than other drugs. This is particularly true when other drug supplies are disrupted.

People experiencing homelessness may use NPS to cope with the pain, trauma or boredom of rough sleeping or hostel living. Understanding this helps when having conversations about drug use with the people you work with.

Some people use NPS without knowing it. Nitazenes in particular are increasingly mixed into heroin, street benzos and fake pills — so someone may be at risk of overdose without realising they have taken anything unusual.

Policy

Your service should have a written drugs policy that covers NPS specifically — not just drugs in general. It should set out what counts as prohibited behaviour, how staff should respond to incidents, how incidents are recorded and escalated, and how harm reduction sits alongside any enforcement action. Staff and residents should both know what the policy says.

Read more here

Recording and monitoring

Recording NPS-related incidents helps you spot patterns, respond to emerging risks and share information with partner agencies.

Keep records simple. For each incident, note the date, the substance if known, the symptoms, the action taken and the outcome. Review records regularly — a cluster of incidents may indicate a particularly dangerous batch in circulation. Share intelligence with your local drug information system (LDIS) and partner agencies. Use the data to report to commissioners and funders.

OHID guidance on local drug information systems - gov.uk

Cross-sector working

Make contact with local drug treatment services, your ambulance service and public health teams before a crisis — not during one.

Ask drug treatment services whether they can offer outreach sessions at your service, staff training, or harm reduction sessions for residents. Connect to your local Combating Drugs Partnership (CDP) to receive alerts about new or dangerous substances in circulation. Where possible, accompany residents to first appointments at drug treatment services to support engagement.

Harm reduction and staff training

Harm reduction starts with how staff talk to residents. Include NPS in routine conversations about drug use. Use non-judgemental language and build the kind of rapport that makes residents feel comfortable disclosing what they are taking. Know what local specialist drug services are available and how to make a referral.

Substance and alcohol use is the third most in-demand knowledge area for frontline workers in the voluntary, community and social enterprise sector, but training remains a significant gap. All staff should have basic NPS awareness — what NPS are, how to recognise them, and how to respond. Staff likely to respond to overdoses should be trained in naloxone administration. A trauma-informed approach helps staff understand why people use NPS and respond without judgement. Peer learning and case discussion can build confidence alongside formal training.

OHID: Guidance for local areas on planning to deal with potent synthetic opioids — gov.uk Practical planning guidance for services and commissioners on responding to synthetic opioids.

OHID: Deaths linked to potent synthetic opioids — gov.uk Latest national data on nitazene-related deaths in England.

Drug information leaflets — crew.scot Free, plain-English harm reduction information on a range of substances including nitazenes.

Drugs and drugs law advice — release.org.uk Free specialist advice on drugs law for individuals and organisations.

Misuse of Drugs Act 1971 (Amendment) Order 2016 — legislation.gov.uk The statutory instrument that brought synthetic cannabinoids under permanent control as Class B drugs in December 2016.

SCRAs within the homeless population: motivations, harms and implications — tandfonline.com Peer-reviewed research from Manchester Metropolitan University and the University of Manchester on why people experiencing homelessness use synthetic cannabinoids and what services can do in response.

ACMD annual report January 2023 to December 2025 — gov.uk Overview of ACMD advice on synthetic cathinones, novel cannabinoids, synthetic opioids and other NPS over the period, including recommendations on classification and public health responses.