Study points to increased risk of harm from cannabis across Europe

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Cannabis resin and herbal cannabis have significantly increased in potency and in price, according to the first study to investigate changes in cannabis across Europe.

The study, published today in the journal Addiction by researchers from the University of Bath and King's College London, draws on data collected from across 28 EU Member states, as well as Norway and Turkey by the European Monitoring Centre for Drugs and Drug Addiction.

The findings show that for , concentrations of delta-9-tetrahydrocannabinol ('THC' - the main psychoactive constituent of cannabis) increased by a similar amount each year, from 5% in 2006 to 10% in 2016.

For cannabis resin (or hash), THC concentrations were relatively stable from 2006 to 2011 (from 8% to 10%) but then increased rapidly from 2011 to 2016 (from 10% to 17%). The price of cannabis resin also increased, but to a lesser extent than for herbal cannabis.

Lead author Dr. Tom Freeman from the Addiction and Mental Health Group within the Department of Psychology at the University of Bath, said: "These findings show that cannabis resin has changed rapidly across Europe, resulting in a more potent and better value product."

Unlike herbal cannabis, cannabis resin typically contains cannabidiol (CBD) in addition to THC. CBD has recently attracted considerable interest due to its potential to treat several including childhood epilepsy syndromes, psychosis and anxiety. When present in cannabis, CBD may offset some of the harmful effects of THC such as paranoia and memory impairment.

Cannabis containing higher levels of THC and / or lower levels of CBD has been linked to greater long-term harms such as the development of cannabis dependence, and an increased risk of psychotic illness. New production techniques in Morocco and Europe have increased levels of THC, but not CBD.

Dr. Freeman added: "CBD has the potential to make cannabis safer, without limiting the positive effects users seek. What we are seeing in Europe is an increase in THC and either stable or decreasing levels of CBD, potentially making cannabis more harmful. These changes in the illicit market are largely hidden from and are difficult to target by policy-makers. An alternative option could be to attempt to control THC and CBD content through regulation."

It is estimated that 24 million people (or 7.2%) of European adults used cannabis in the last year. Across the globe 192 million people use the drug in a variety of markets, ranging from heavily sanctioned prohibition to commercialised legal sale. Cannabis policies are rapidly changing across the globe.

Recreational use is now legalised in Canada and several US states, and medical use is permitted in many more countries, including very recently in the UK.

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More information: Tom P. Freeman et al, Increasing potency and price of cannabis in Europe, 2006-2016, Addiction (2018). DOI: 10.1111/add.14525
Journal information: Addiction

Provided by University of Bath
Citation: Study points to increased risk of harm from cannabis across Europe (2019, January 1) retrieved 21 October 2019 from
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Jan 01, 2019
This comment has been removed by a moderator.

Jan 01, 2019
Nice propaganda piece. The title implying there is true real research done but....not. a few "factoids" hinting at maybe something kinda we think. Disappointing

Jan 01, 2019
Like all things - moderation...

Jan 01, 2019
Pretty well all of what the USA is right now was borne out of the privatization of the prisons, control of the judiciary, and the legally created policies, drug running by the CIA for wiping out countries and installing governments, and running it at home.

this was the genesis of the USA as a 'stinking fascist torture police state', that it is now.

Most of this 'high gear high speed mode' came about through George bush senior.

So yes, the mess of the world for the sake of the us hegemony, one of the chief architects of the mess the world is in, can be laid at the feet of this horrid thing called a George Bush senior.

And the mess of the drug policies was created and pushed by him and the apparatus he was driving and running.

The comments here on how 'bad' it is, is from either inside it as a propaganda push,or incredibly uninformed in history and reality.

Jan 01, 2019
the unreported scandal is the removal of trichomes for production of oil and hash, prior to selling the now diminished flowers as top-shelf product.

Jan 02, 2019
Exactly the result you'd expect from "Addiction" researchers. They gotta eat, too. In fact, cannabis is safe as milk.

... AND way safer than the No. 1 drug of choice for most, which is alcohol --- a drug so dangerous it was banned in the USA despite its deeply rooted popularity. Marijuana prohibition was enacted in part to give federal drug police a mission after the repeal of alcohol prohibition. Until 1937, cannabis was widely used in over-the-counter medicines because it is very effective in treating neurological disorders.

Jan 02, 2019
30% THC bud is readily available where I live. It goes for $10-12 a gram. For comparison, low-potency (10-15% THC) runs about $2-4 a gram.

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