Article

Mongan, Deirdre (2026) New psychoactive substances identified in Ireland 2021–2025. Drugnet Ireland , Issue 94, April 2026 , pp. 1-4.

Millar, Seán R (2026) Hexahydrocannabinol use and harms in Ireland. Drugnet Ireland , Issue 93, February 2026 , p. 32.

Millar, Seán R (2026) Hexahydrocannabinol and psychosis: trends in Ireland’s mental health landscape. Drugnet Ireland , Issue 93, February 2026 , p. 31.

Dillon, Lucy (2026) The 68th session of the Commission on Narcotic Drugs. Drugnet Ireland , Issue 93, February 2026 , pp. 12-13.

O'Mahony, Brian and Lanigan, Sarah and Lally, Níall and O'Malley, Andrew and Smyth, Bobby and McDonald, Colm and Hallahan, Brian (2025) Novel substance, same old problems: admissions of psychosis precipitated by hexahydrocannabinol, a widely available semi-synthetic cannabinoid. BJPsych Bulletin , pp. 1-6.

Millar, Seán (2025) Psychotic illness triggered by widely available semi-synthetic cannabinoid. Drugnet Ireland , Issue 90, Winter 2025 , p. 15.

Mongan, Deirdre and Killeen, Nicki and Millar, Seán R and Matias, Joao and Keenan, Eamon and Galvin, Brian (2025) Hexahydrocannabinol (HHC) use and harms in Ireland: new findings from the 2024 European Web Survey on Drugs. International Journal of Drug Policy , 145 .

O'Mahony, Brian and O'Malley, Andrew and Kerrigan, Olan and McDonald, Colm (2024) HHC-induced psychosis: a case series of psychotic illness triggered by a widely available semisynthetic cannabinoid. Irish Journal of Psychological Medicine , 41 , (3) , pp. 405-408.

Report

College of Psychiatrists of Ireland. (2024) HHC and your mental health: information about Hexahydrocannabinol (HHC) and how it might affect your mental health. Dublin: College of Psychiatrists of Ireland.

European Monitoring Centre for Drugs and Drug Addiction. Ujváry, István and Evans-Brown, Michael and Gallegos, Ana and Planchuelo, Gregorio and de Morais, Joanna and Christie, Rachel and Jorge, Rita and Sedefov, Roumen (2023) Hexahydrocannabinol (HHC) and related substances. Technical report. Luxembourg: Office for Official Publications of the European Communities.

Webpage

European Monitoring Centre for Drugs and Drug Addiction, Europol. (2024) EU drug market: New psychoactive substances — Distribution and supply in Europe: semi-synthetic cannabinoids. URL: https://www.euda.europa.eu/publications/eu-drug-ma...

European Monitoring Centre for Drugs and Drug Addiction, Europol. (2023) EU drug market: cannabis — in-depth analysis. URL: https://www.euda.europa.eu/publications/eu-drug-ma...

FactSheet

Ireland. Department of Health. (2025) HHC (Hexahydrocannabinol). Dublin: Department of Health.

Jordan, Deborah (2024) HHC/vaping: what is it? Wicklow: East Coast Regional Drug and Alcohol Task Force.

Dail Debates

[Oireachtas] Dáil Éireann debate. Questions 274; 275, 276 - Revenue Commissioners [vaping] [40869/26, 40870/26, 40871/26]. (28 May 2026)

[Oireachtas] Seanad Éireann debate - An tOrd Gnó - Order of Business [Synthetic cannabinoids]. (29 Apr 2026)

[Oireachtas] Dáil Éireann Debate. Question 1157 - Substance misuse [47833/25]. (17 Sep 2025)

[Oireachtas] Dáil Éireann debate. Question 2728 – Misuse of drugs [HHC] [41719/25]. (29 Jul 2025)

[Oireachtas] Dáil Éireann debate. Question 2678 – Medicinal products [HHC] [41325/25]. (29 Jul 2025)

[Oireachtas] Dáil Éireann debate. Question 2716 – Legislative measures [HHC] [41666/25]. (29 Jul 2025)

[Oireachtas] Dáil Éireann debate. Question 336 – Healthcare policy [Vapes, pouches, HHC] [38401/25]. (10 Jul 2025)

[Oireachtas] Dáil Éireann debate. Question 859 – Misuse of drugs [HHC] [37721/25]. (08 Jul 2025)

[Oireachtas] Dáil Éireann debate. Question 1585, 1614, 1615 – Healthcare policy [HHC] [30333/25, 30523/25, 30524/25]. (10 Jun 2025)

[Oireachtas] Dáil Éireann Debate. Question 584 – Tobacco control measures [HHC vapes] [26759/25]. (27 May 2025)

[Oireachtas] Dáil Éireann Debate. Question 324 – Misuse of Drugs [24971/25]. (15 May 2025)

[Oireachtas] Dáil Éireann debate. Question 203 - Health promotion [HHC products] [24020/25]. (13 May 2025)

[Oireachtas] Seanad Éireann debate. Vol. 305 No. 10 An tOrd Gnó - Order of Business [HHC products]. (07 May 2025)

[Oireachtas] Dáil Éireann debate. Question 327 – Tobacco control measures [16166/25]. (02 Apr 2025)

[Oireachtas] Dáil Éireann debate. Questions 98 & 121 - Substance misuse [10125/25]. (06 Mar 2025)

[Oireachtas] Dáil Éireann debate. Question 664 – Substance misuse [HHC] [17930/24]. (23 Apr 2024)

[Oireachtas] Dáil Éireann debate. Question 270 – Substance misuse [HHC hexahydrocannabinol]. (22 Feb 2024)

[Oireachtas] Dáil Éireann debate, Topical issue debate – Departmental regulations [Synthetic cannabinoid HHC]. (20 Feb 2024)

[Oireachtas] Dáil Éireann debate. Question 1499 – Misuse of drugs [cannabinoids] [56526/23]. (17 Jan 2024)

[Oireachtas] Dáil Éireann debate. Questions 236 - Health Service Executive [Cannabinoids in vapes] [34427/23]. (12 Jul 2023)

[Oireachtas] Dáil Éireann debate. Questions 456, 620, 621, 622 - Substance misuse [Cannabinoid vaping] [30556/23, 30553/23, 30554/23, 30555/23]. (27 Jun 2023)

Video

HSE Health and Wellbeing. (2025) Parents matter – vaping products & psychoactive substances: what you should know as a parent. Health Service Executive.

News

[Irish Examiner] , Cunningham, Alex Synthetic cannabis driving mental health issues, warns HSE official. (04 Jun 2026)

Ireland. Department of Health. [Department of Health] Ministers for Health announce that HHC is now classified as an illegal drug. (29 Jul 2025)

[thejournal.ie] , Sherlock, Marie Time to face the reality of synthetic drug use among young people. (26 Jul 2025)

[RTE News] , Kenny, Aisling 169 young people sought treatment for HHC drug in last 18 months - Health Research Board. (30 Jun 2025)

[Limerick Post] , English, Bernie Limerick teens sent to psych wards after using legal vape substance. (26 Jun 2025)

[Irish Examiner] , Murphy, Ann HHC: The drug sold on Irish main streets that’s sending teens to hospital. (17 May 2025)

[Irish Times] , Bowers, Shauna Teens presenting at EDs with psychosis from legal, semi-synthentic cannabis product, says leading psychiatrist. (26 Mar 2025)

[Irish Examiner] , Murphy, Ann 'Wild West of the drug market': calls for laws to deal with synthetic cannabinoids. (10 Mar 2025)

[Irish Examiner] , Dunphy, Liz Vapes with cannabinoids causing psychosis in users as young as 13. (25 Nov 2024)

[RTE News] , Burnhill, Eleanor Arrival of synthetic drugs causing mental health concerns, says HSE. (05 Jan 2024)

[Extra.ie] , MacNamee, Garreth ‘Legal high’ drug inhaled through a vape puts four teens in hospital. (23 Nov 2023)

[EMCDDA] EMCDDA technical expert meeting on hexahydrocannabinol (HHC) and related cannabinoids. (19 Dec 2022)