The College of Psychiatrists of Ireland has said it “beggars belief” that products containing a man-made drug which produces similar effects to cannabis, and which it says has done major damage to people’s mental health, are still available without restrictions in this country.
The college issued its statement as a new study examining the use of the drug Hexahydrocannabinol or HHC, found it was the second most common drug, after cannabis, involved in patients presenting with psychosis at University Hospital Galway between May 2023 and December 2024.
The drug contained in some vapes and edibles, produces similar effects to the natural ingredient in cannabis – THC – which causes the drug’s high.
The products are available to buy for anyone over 18, despite ongoing calls for them to be banned.
The study was published by Cambridge University Press on behalf of the Royal College of Psychiatrists.
It involved an examination of the medical notes of 214 admissions for psychotic illness to the Adult Acute Mental Health Unit at University Hospital Galway – over a period of 21 months from May 2023 to December 2024.
The researchers found that 28 of the admissions were preceded by self-reported use of HHC.
Nine of these admissions reported using only HHC while the others used other substances such as cannabis, cocaine and psychedelics.
The study found that HHC users were more likely to be male and ranged in age from 18 to 49 with a median age of 24 – significantly younger than the median age of those who did not use HHC.
HHC was the second most used illicit substance in the admissions, with cannabis being the most used.
When the researchers examined those admitted for a first episode of psychosis, they found that out of 47 such individuals, 16 were preceded by HHC use.
The researchers say that to their knowledge, this is the first study to examine the prevalence rates of HHC use in people experiencing acute psychotic disorders.
The chief executive of a company that makes and sells Hexahydrocannabinol or HHC, a drug contained in some vapes and edibles, has said he believes there needs to be more regulation in Ireland around selling the substance.
Luke Gavin, CEO and Founder of Owls Oil, said that in his opinion the issue comes back to education and that he believes some people may be taking “too much”.
He said that because of the lack of regulation here there are issues in relation to the supply chain and testing of the products.
Researchers, meanwhile, say HHC is now the second most common drug involved in psychosis presentations.
However, they say this aligns with previous data when other psychoactive substances were available legally in head shops.
They acknowledge limitations in this survey and say it is likely that it underestimates the prevalence of HHC.
This is because toxicology tests may give a false positive for THC, and a lack of awareness about the prevalence of HHC may mean patients were not directly asked about it.
They also point out that when asked a question about illegal drug use, patients may not have mentioned HHC as it is not an illegal substance.
They also point out that the study looks only at people experiencing severe or very acute psychotic episodes and not those who were managed as out patients.
They do acknowledge that the results of this survey in one hospital may not apply generally.
However, the researchers say the results lend further support to a link between HHC use and psychotic illness.
The study raises concern about the ability of Irish legislation introduced in 2010 to regulate products sold in head shops, to prevent the sale of HHC products and the sale of future “novel psychoactive substances”.
They say the delay in banning HHC and its “longstanding, tolerated and ongoing sale”, has already led to significant harm for a number of individuals and failure to react more quickly to the next new substances will likely cause future harm.
Asked about the study, Mr Gavin said there was a “big issue” in Ireland because people were unsure how to consume it and they may take too much.
Mr Gavin said dosing was extremely important and he said he believed it was a better alternative to alcohol and that many people were using it to relax.
In a statement, the College of Psychiatrists said HHC was a particularly harmful substance that had done major damage to the mental health of many people – adolescents in particular – in just a few years since its creation.
It said it beggared belief that it was still freely available around Ireland without any restrictions, given the “overwhelming evidence” of its harms.
The statement added that the legislative framework existed for the Government to ban it and it called on the Government to act urgently to do so “before more people and their loved ones were negatively impacted”.
