The EU is being flooded with super-strength cannabis that puts users at greater risk of psychosis, the bloc’s drugs monitoring agency has warned.
Alexis Goosdeel, director of the EU Drugs Agency, said some cannabis circulating today was five times stronger than “the pot that was smoked at Woodstock”, the counterculture music festival of 1969.
“It’s a concern because with such a high potency, the probability of it being the cause of a psychotic episode or other mental health issues is much higher,” Goosdeel told the Financial Times.
The warning comes as five EU countries, including Germany, the Netherlands and Czech Republic, implement or develop plans to further legalise the drug.
Goosdeel said the rising potency of cannabis, which has been deliberately engineered by drug producers, was not necessarily a reason to rethink those plans. Instead he argued that legalisation could give the authorities a chance to impose clear limits on cannabis strength.
Cannabis is Europe’s most widely used illicit drug with an estimated 8.4 per cent of adults, or 24mn people, consuming it in the past year, according to the drug agency’s annual report published on Thursday.
According to analysis of chemical traces in city wastewater, Amsterdam and Groningen in the Netherlands are among Europe’s top users of cannabis, followed by Barcelona and Tarragona in Spain, then Oslo and Lisbon.
Cannabis’s key component is THC, a psychoactive ingredient that creates the sensation of a “high”, and the drugs agency said its presence in cannabis resin in Europe had almost doubled from 2013 to 2023.
The average THC content of the resin — a sticky substance that is mixed with tobacco or infused into edibles — is now 23 per cent, versus 11 per cent in the herbal cannabis leaves that can be smoked directly. Goosdeel said Woodstock pot was closer to 4 per cent.
Medical studies have found that regular cannabis use, especially in high doses, can cause hallucinations, delusions and paranoia in some people. In teenagers and young adults it has been linked to a higher risk of chronic psychotic illnesses, including schizophrenia.
“There is strong evidence that the impact in terms of psychotic episodes seems to be associated with the fact that some people have a vulnerability. But there is no way to detect the vulnerability” in advance, said Goosdeel, who will step down later this year after leading the Lisbon-based agency for a decade.
Last year Germany decriminalised the possession of small amounts of cannabis and permitted the cultivation of plants at home. Luxembourg, Malta and the Czech Republic have made or planned similar moves.
The Netherlands — Europe’s pioneer in cannabis legalisation — is experimenting with ways for its famous “coffee shops” to buy drugs from a regulated supply chain rather than criminal gangs.
Goosdeel noted that after Uruguay legalised cannabis in 2013 sales did not take off as expected, partly because the legal product was weaker than what was available in the black market.
In response the authorities decided to increase the potency of legal cannabis “to make it a competitive product”, while remaining within what they deemed to be safe limits.