HERBAL CANNABIS produced in Ireland has a higher potency than the imported variety, creating a greater risk of damage to people’s health, according to new research.
The study, by the Forensic Science Laboratory, which operates out of Garda headquarters in Dublin, analysed cannabis products to establish their tetrahydrocannabinol (THC) content.
THC is the main psychoactive component of cannabis.
There is increasing international concern about rising THC levels, particularly in herbal cannabis of the “skunk” or “weed” variety, given its side effects on the brain, which can include psychosis.
Dr Des Corrigan, chairman of the National Advisory Committee on Drugs which commissioned the research, said: “Many of the plants being grown here are genetically selected to ensure they produce high levels of THC, but they also lack a substance called cannabidiol (CBD), which seems to protect the brain from the effects of THC.”
Samples from seizures of the cannabis herb in Limerick, Cork, Tipperary, Bandon, Fermoy and Dublin found cannabis that was of Irish cultivation had very high THC levels and very low CBD levels compared to imported herb and resin (hash).
High levels of THC in cannabis raises serious health concerns, according to Dr Corrigan.
“Recent studies in the UK have shown that there is a higher risk of psychosis in those who smoke high-potency cannabis products compared to those who smoke hash which contains both THC and CBD,” he said.
Cannabis is the most commonly used illicit drug in Ireland.
The plants cannot be grown outdoors in Ireland because of the climate so instead are grown indoors using hydroponics and intensive lighting equipment.
This growing method produces more THC.
In many cases, female rather than male plants are used as they cannot produce seeds, meaning all the energy within the plant goes into the production of THC content, increasing the plant’s potency.
“Monitoring the potency of cannabis is extremely important,” Dr Corrigan added.
The majority of cannabis products seized by gardaí in Ireland are thought to be imported from countries where it is specifically grown for exportation.