Cannabis-like drug causing severe psychosis in young men, College of Psychiatrists warn

Hexahydrocannabinol is legal in Ireland and commonly available in the form of vapes or added to jellies or chocolate

Hexahydrocannabinol (HHC) is sold widely in shops in Ireland and often marketed as a safer or less strong alternative to cannabis. Photograph: iStock

A new cannabis substitute is causing severe psychosis in young men that requires months of intensive in-patient treatment, the College of Psychiatrists has warned.

Hexahydrocannabinol (HHC), which first emerged in 2022, is chemically similar to Tetrahydrocannabinol (THC), the active ingredient in cannabis, and produces comparable physiological effects.

HHC is commonly available in the form of vapes or added to jellies or chocolate. It is legal in Ireland and has become increasingly popular here in the last year. It is sold widely in shops and is often marketed as a safer or less strong alternative to cannabis.

The College of Psychiatrists said HHC is a factor in about 20 per cent of presentations to adolescent addiction services. It has called on the Government to ban HHC using legislation introduced in 2010 to tackle a surge in dangerous but legal substances being sold from so-called head shops around the country.

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Prof Bobby Smyth, specialist consultant child and adolescent addiction psychiatrist, said these head shops caused a huge amount of damage to young people and “we are seeing a similar trend now with HHC”.

Prof Colin O’Gara, consultant specialist addiction psychiatrist, said HHC was initially seen as a harmless drug but can have devastating effects on the mental health of young people. “We have treated young men suffering from severe psychoses as a result of vaping HHC. These individuals can require months of intensive treatment in the in-patient setting with medication to recover from the psychosis.”

The College of Psychiatrists published a guide on Monday outlining HHC’s effects and risks.

Prof Smyth, who is chair of the college’s faculty of child and adolescent psychiatry, said there has been an “extraordinary” rise in HHC-related addiction presentations among adolescents in “a short period of time”.

“HHC was only identified in Europe for the first time two years ago. Today, we estimate that HHC now features as a component part in about 20 per cent of all presentations to adolescent addiction services in Ireland, very often in combination with cannabis itself,” he said.

One of the worrying elements of HHC use was that no one knows its long-term consequences, Prof Smyth added.

“The public need to know that just because a substance is sold in a shop, in fancy packaging, for human consumption, it does not mean that it is safe or tested in any meaningful way. Until proven otherwise, we should work on the assumption that HHC products are going to cause the same mix of problems which we see with cannabis,” he said.

The college called on the Government to include HHC on the list of prohibited substances, enforce the legal prosecution of businesses and retailers distributing and selling any version of the drug, and to raise awareness of the potential dangers or harms of HHC, particularly aimed at young adults and schools.

Conor Gallagher

Conor Gallagher

Conor Gallagher is Crime and Security Correspondent of The Irish Times

Jade Wilson

Jade Wilson

Jade Wilson is a reporter for The Irish Times