A new study has examined the links between HHC and psychosis presentations at the adult acute mental health unit at UHG.
Hexahydrocannabinol is essentially a synthetic form of cannabis - and it's legally available in shops here, but banned in many parts of Europe and the UK.
The Royal College of Psychiatrists says this is the first study to examine prevalence rates of HHC use in individuals experiencing acute psychotic disorders.
They looked at 214 patients that were admitted for psychosis symptoms at UHG between May 2023 and December 2024.
It found that 13 percent of those had taken HHC and it's now the second most common drug involved in psychosis presentations behind cannabis.
A third of admissions for first-episode psychosis - 16 cases - were preceded by HHC use.
Researchers say the study likely underestimates the real use and impact of the semi-synthetic cannabinoid.
That's partly due to the fact that a patient can truthfully say they haven't taken illicit or illegal drugs, because HHC is entirely legal to buy and consume in Ireland.
There's also the fact that some patients experiencing psychosis will not require admission to the in-patient unit and so are not captured in the study.
But they conclude there's a definite link between HHC and psychosis - that people need to be more aware of its dangers - and the longstanding, tolerated and ongoing sale of HHC in Ireland has harmed many people.
The study was carried out by researchers at University of Galway.
