A new psychoactive substance (NPS) can be described as a new narcotic or psychotropic drug, in pure form or in preparation, that is not controlled by the United Nations drug conventions, but which may pose a public health threat comparable to that posed by substances listed in these conventions. Health harms associated with NPS range from seizures to agitation, aggression, intoxication, acute psychosis as well as dependence.

In order to rapidly detect and assess threats posed by NPS, the European Union Early Warning System (EWS), was established by the European Union Drugs Agency (EUDA) in 1997. The system is composed of a multisectoral, multidisciplinary, and multiagency network, which includes the EUDA, 29 national early warning systems (27 European Union Member States, Turkey, and Norway), Europol and its law enforcement networks, the European Medicines Agency, and the European Commission.

When an NPS is identified for the first time in a country, that country’s national early warning system reports this to the EUDA; the report includes chemical and analytical information, as well as the circumstances of the event. If this is the first time the NPS has been identified in Europe, a formal notification is circulated by the EUDA through the national early warning systems.

Between 2021 and 2025, 57 new NPS were reported by Ireland (via the Health Research Board (HRB)) to the EUDA (Table 1); 45 NPS were identified through seizures from Forensic Science Ireland, and 12 were collected samples from the Health Service Executive (HSE) National Drug Treatment Centre. Almost all collected samples were obtained through the HSE ‘back of house’ drug checking service that has been provided at a number of festivals in Ireland since 2022. Cannabinoids were the most common NPS identified, with semi-synthetic cannabinoids identified for the first time in 2023. Four opioid NPS were identified; all were nitazenes, which have been responsible for a considerable number of poisonings both in Ireland and in other European countries. For three NPS identified in Ireland – Hexahydrocannabinol-C8, 6-(4-chlorophenyl)-1-methyl-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepine, and 1-[2-(3,4-dimethoxyphenyl)-1-methylethyl]-pyrrolidine – this was the first time each was identified in Europe.

According to the EUDA, the availability of NPS in Europe is at an historic high. There are currently in excess of 1,000 NPS being monitored by the EUDA, with 47 NPS notified for the first time in 2024. Emerging threats include semi-synthetic cannabinoids in vapes and edibles, and highly potent nitazene opioids.1

A full list of all NPS identified in Ireland from 2021 to 2025 is provided in Table 2.

Table 1: NPS identified in Ireland 2021–2025, by drug type

Table 2: Full list of NPS identified in Ireland from 2021 to 2025

1    European Union Drugs Agency (2025), European Drug Report 2025: Trends and Developments. Available from: https://www.euda.europa.eu/publications/european-drug-report/2025_en