Ireland's delay in banning HHC may have boosted demand 

Vapes are the most common method of taking HHC (85%), followed by edibles in the form of candies and gummies (34%). Picture: iStock

Use of a semi-synthetic form of cannabis has become “widespread” in Ireland in a relatively short timeframe, according to research.

Hexahydrocannabinol (HHC) was legally available in Ireland — mostly through vape shops — despite the strong concerns of medical experts, until the Government eventually banned its sale last July.

A study, described as the first European analysis of HHC use in the population, said it was possible the “delay” in controlling HHC in Ireland had “contributed to its popularity”.

HHC is a semi-synthetic cannabinoid, where the chemical is sprayed onto cannabis, typically low-grade quality.

Data from 2,314 Irish people

Research by the Health Research Board, the HSE, and the School of Public Health at University College Cork examined data from 2,314 Irish people who took part in the 2024 European web survey of drugs.

Of these respondents:

• 36% reported lifetime use (at least once in their life);
• 33.5% reported use in the last year;
• 18% said they had used HHC in the last month.

The study, published in the International Journal of Drug Policy, said high street stores were reported as the main source of HHC (62%), with a further 16% buying it from an online store.

Vapes were the most common method of taking HHC (85%), followed by edibles in the form of candies and gummies (34%).

“The primary motive for first using HHC was its easy availability in stores (61.5 %), followed by a sense of safety in buying from a store (46.1%), and friends using HHC (36.1 %),” the study said.

Consequently, it is possible that the delay in controlling HHC in Ireland has contributed to its popularity.

“Importantly, as HHC could be freely and legally purchased in Ireland until very recently, there may have been a perception among users in our sample that it is ‘safer’ than cannabis or synthetic cannabinoids that were controlled by legislation.

“This is of concern as, in addition to the unknown short- and long-term effects of HHC, the [European Union Drugs Agency] has noted that HHC products may contain harmful contaminants from production.”

It said the most common reasons for using HHC were to get high or for fun (62.9 %) and to reduce stress or relax (51.9 %).

It said respondents reported using HHC to treat a number of physical and mental ailments: 

• 27.3% used it to manage depression or anxiety; 
• 18.2% used HHC to reduce pain or inflammation; 
• 5.6% used it to manage cannabis withdrawal symptoms.

Respondents reported frequent usage, with almost a third using it 1-10 days and another third using it 11-50 days.

Nine out of 10 people reported negative effects, with almost a quarter reporting two harms.

The most frequent was anxiety or panic reactions (15%), followed by feeling faint of dizzy (13%) and dissociation or depersonalisation (12%). Hallucinations or psychosis was reported by 4% of respondents. The study said: 

HHC has become increasingly available in Europe and the results presented in this study suggest that, in a relatively short period of time, HHC use has become widespread in Ireland.

The authors said the HHC situation mirrored that for New Psychoactive Substances (NPS), which were widely available in ‘head shops’ before The Psychoactive Substances Act 2010.

However, the authors said that, despite the existence of this legislation, HHC remained legal “long after its psychoactive properties were confirmed”.

It said that, ultimately, HHC was controlled under the Misuse of Drugs Act, rather than the 2000 act.

Ireland may need to review drug laws 

It suggested a review of drug laws may be required to ensure it is fit for purpose.

“This may enable Ireland to more swiftly response to the rapidly evolving drug market,” the study said.

The authors said it was not possible to conclude that the sample in the research they examined could be generalised to the population of HHC users in Ireland.

The research was conducted by Deirdre Mongan and Brian Galvin, attached to the HRB, Eamon Keenan and Nicki Killeen of the HSE, Seán Millar of the HRB and UCC, and Joao Matias of the EU Drugs Agency.

Concerns regarding HHC were documented, including extensively in the Irish Examiner as far back as November 2023, when four teenagers from a school in Cork became ill and were hospitalised after vaping, with analysis identifying HHC.

In February 2024, psychiatrists and doctors from the University of Galway and Mercy University Hospital Cork said HHC was "readily available" online and in retail vape shops.

The research said the drug should be included as a "psychoactive substance" under the Criminal Justice (Psychoactive Substances) Act 2010.

In May 2024, the HSE clinical lead on addiction, Eamon Keenan told the Irish Examiner that around 20% of young people presenting to adolescent addiction services in recent months were associated with HHC.

Prof Keenan said he was building a case for the Department of Health to include HHC in existing drug laws and have its sale banned.

In August 2024, Forensic Science Ireland highlighted the presence of HHC among, what it said was, a “Wild West” of synthetic and semi-synthetic cannabinoids.

The College of Psychiatrists repeatedly raised concerns about the substance.

In May of this year, an Irish Examiner investigation highlighted the ease with which people, including children, could buy products containing HHC.