Cannabis Strength Doubles

Cannabis Now Twice As Strong As A Decade Ago

Frightening Study Results on the Strength of Cannabis in Europe Over the Past Eleven Years

The study mentioned here was carried out by researchers from University of Bath and King’s College London and is the first ever study to monitor the changes and trends in Cannabis in Europe. The frightening discovery was that the potency of Cannabis in Europe has doubled over a period of just 11 years! Dr Tom Freeman from the Department of Psychology at King’s College London and University of Bath led the study, the results of which were published in the appropriately-named journal, Addiction.

The Study

The researchers collected data for the EMCDDA – the primary monitoring centre in Europe that looks at drugs and addiction – across 28-member states of the European Union, including Turkey and Norway, and their estimate is that upwards of 24 million Europeans consumed cannabis in some form over the past 12 months. This equates to more than 7% of the adult population in Europe. Globally, it is estimated that more than 190 million adults consume cannabis, in a variety of markets ranging from commercialised legal sale through to heavily sanctioned prohibition.

The outcome of this study is concerning because this jump in potency can have dangerous consequences for users of Cannabis. The study revealed that both herbal cannabis and cannabis resin have become disturbingly stronger and more potent.

Why Are the Study Results So Worrying?

THC, which stands for tetrahydrocannabinol, is the primary psychoactive ingredient in herbal Cannabis, and there has been an increase in THC from approximately 5% in the year 2006 to a worrying 10% in the year 2016. It’s the THC in Cannabis that’s been linked to psychosis. However, even though the concentrations of THC rose rapidly in Cannabis resin from 10% in 2011 to 17% in 2016, the concentrations in herbal cannabis were largely stable between the years 2006 and 2011. This means that, in Europe, cannabis resin is now a much more potent product. The increase in the potency of Cannabis resin is believed to be due to improved production methods in Europe and Morocco.

So, while we’re now seeing an increase in THC levels, the level of CBD (which stands for cannabidiol) has either stayed the same, or reduced. This is concerning because it’s believed that CBD in Cannabis resin does offset some of the negative effects.

THC and CBD: The Differences

Both THC (tetrahydrocannabinol) and CBD (cannabidiol) are derived from the cannabis plant. Both form part of the cannabinoid group of compounds found in most strains of marijuana, hashish, and hash oil. The high euphoric feeling typically associated with marijuana use is due to the THC, which creates the sensations of anxiety and euphoria. CBD is not psychoactive and actually decreases THC’s effects. In fact, it’s believed that CBD reduces inflammation and anxiety.

It’s CBD that makes Cannabis safer for users by offsetting many of THC’s most dangerous effects, like memory impairment and paranoia, without diminishing the effects that Cannabis users are seeking. This rise in THC and stable or reducing CBD levels is cause for concern, because Cannabis has now become potentially more harmful.

How Much Does Cannabis Cost?

Between the years 2006 and 2016 there was an increase in the price of herbal cannabis from €7.36 to €12.22 per gram, while the price of cannabis resin over the same period increased from €8.21 to €12.27. Police seizures in the UK suggests that, while THC levels in herbal cannabis stayed relatively stable between 2006 and 2016, levels of cannabis resin have risen sharply.


Doctor Tom Freeman said that these findings show that cannabis resin has become a more potent and better-value product, and that while the study shows THC increasing alongside decreasing or stable CBD levels, cannabis has potentially become more harmful to users. Obviously, it’s difficult for policymakers to target these changes, however Dr Freeman believes that one option might be to use regulation to control the CBD and THC levels in herbal cannabis.

Photo Credit: “Veer Guest House” (CC BY 2.0) by PabloEvans

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