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Expert Reaction: Study of cannabis potency in the UK

Posted on 28 February 2018

Mental health lecturer Ian Hamilton comments on new research which reveals that the UK cannabis street market is increasingly dominated by very high potency varieties of the drug.

The new study looked at seized samples of cannabis to assess the potency of common types of the drug on UK streets.


“If these seized samples are representative then it suggests that apart from the dominance of skunk in the UK market, it also seems that resin has increased in strength, as this analysis shows that some resin samples were nearly three times stronger than those seized back in 2005. So even if people are trying to source lower potency cannabis they are unable to.


“This paper did not look at mental health effects, it just looked at the state of cannabis in the UK. But we know from previous research that cannabis with higher levels of THC (tetrahydrocannabinol) and lower CBDs (cannabidiols) are associated with risks to mental health, so if the cannabis market is saturated with higher potency cannabis this increases the risk of younger and more naive users developing problems as they are less likely to adjust the amount of cannabis they ingest than more experienced users.”

Potency of Δ9–tetrahydrocannabinol and other cannabinoids in cannabis in England in 2016: Implications for public health and pharmacology is by David J. Potter et al and is reported in Drug and Testing Analysis.

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