How hash and weed all but disappeared from Britain's streets, as high-strength ‘skunk’ took over

'Cannabis users, growers, dealers, drug workers, police I've talked to have been saying the market has been dominated by strong weed for the last decade', says drug expert

A new report has found the UK cannabis market is dominated by high-potency “skunk” and weaker varieties of the drug have been pushed out.

The study, conducted by King’s College London researchers, found high-potency varieties constituted 94 per cent of police seizures in 2016.

The piece of research is the first comprehensive, wide-ranging survey of cannabis strength published in Britain for almost 10 years.

Researchers examined almost 1,000 police seizures of cannabis from London, Kent, Derbyshire, Merseyside and Sussex – areas which were last investigated in 2005 and 2008.

In 2016, 94 per cent of police seizures were high-potency sinsemilla – colloquially referred to as “skunk” – compared to 85 per cent in 2008 and just 51 per cent in 2005.

The research focused on the potential risk posed to users’ mental health in a market saturated by strong forms of cannabis.

Dr Marta Di Forti, MRC Clinician Scientist at King’s College London’s Institute of Psychiatry, Psychology & Neuroscience, and senior author of the report, said: “In previous research we have shown that regular users of high-potency cannabis carry the highest risk for psychotic disorders, compared to those who have never used cannabis.”

She added: “The increase of high-potency cannabis on the streets poses a significant hazard to users’ mental health, and reduces their ability to choose more benign types.”

Max Daly, a drug expert, said he was not remotely surprised the research found high-strength ”skunk” dominates the UK market.

“Cannabis users, growers, dealers, drug workers, police I’ve talked to have been saying the market has been dominated by strong weed for the last decade. This is backed up by research, forensics, experts, academics”, Mr Daly told The Independent.

Mr Daly, who wrote Narcomania: How Britain got hooked on drugs with Steve Sampson, said there were a number of reasons less potent varieties of marijuana had dwindled and been superseded by skunk.

“It’s a mixture of clampdown by Moroccan government on resin trade so the UK resin supply sharply reduced”, he said. “Then into this gap in the market we have Vietnamese cannabis factory gangs coming to the UK, teaming up with UK domestic gangs, to grow and sell the skunk type weed.

“Also there has been a rise in online growing kits and advice. Now the Vietnamese have largely disappeared and cannabis farming is now big business for anyone from kids to organised crime groups. Also weed is still imported into this country mainly from Holland. There is now a lack of choice for consumers, and seems to be all about growing and smoking stronger weed, rather than the mellow hash of the 90s.”

Mr Daly, a journalist who specialises in the drug trade and writes a regular column for Vice UK, also drew attention to the fact growing cannabis in Britain is more cost-effective than importing hash from another country.

The study, published in the journal Drug Testing and Analysis on Monday, found the dominance of sinsemilla was chiefly related to a sharp reduction in the availability of weaker cannabis resin. This has gone from 43 per cent in 2005 and 14 per cent in 2008, to just six per cent in 2016, but as low as one per cent in the vicinity of London.

The average concentration of THC - the predominant psychoactive component of marijuana – in resin also increased from 4 per cent to 6 per cent. The average concentration of THC in sinsemilla has remained at 14 per cent between 2005 and 2016.

Explaining the difference between CBD and THC in “skunk” to hash in layman’s terms, Mr Daly said: “High strength weed/skunk type cannabis has way more THC which gets you high and less CBD which counters THC than hash. So you get way more stoned.”

In other words, CBD’s antipsychotic effects mean it might moderate and curb some of the effects of THC.

Alterations in the source of cannabis plants used for resin has led to a drop in CBD content. To put this into context, in 2005 and 2008, the ratio of THC to CBD was 1:1, whereas in 2016 the ratio was 3:1.

A recent King’s College London study found the first evidence for a link between rises in cannabis potency and first-time admissions to drug treatment by looking at data from the Netherlands.

“More attention, effort and funding should be given to public education on the different types of street cannabis and their potential hazards. Public education is the most powerful tool to succeed in primary prevention, as the work done on tobacco use has proven”, Dr Di Forti said.

Mr Daly said he imagined there were some teenagers in the UK who would never have heard of hash and weed and have only been exposed to high-potency ”skunk”.

“Yes many teenagers have grown up on diet of very strong skunk type cannabis, and it’s caused rising problems with mental health among young cannabis users in the UK”, he said.

“However I’ve heard that there is a return in some circles – mainly buying over the web - of hash by adults and that this is filtering down to young people.”

He added: “All the evidence I’ve seen is that very strong cannabis is, of course, impacting some young people more in terms of their mental health than less strong hash. But also there has been gradual fall in cannabis use in the UK – some say this is due to lack of choice eg skunk or skunk so puts many off smoking it.”