Evidence and Ignorance – A Potent Mix

by Paul North



A new KCL study shows that cannabis potency could be a key contributing factor in levels of problematic use. The study is the first of its kind to show a correlation between changes in cannabis potency and admissions to drug treatment services.

The research, which was funded by the Society for the Study of Addiction, tested 1000 cannabis samples over a period of 16 years. The samples tested were always the most popular high potency strains of cannabis available in coffee shops around the Netherlands. At the same time, the study looked at the number of first time presentations in drug treatment for cannabis use. The study found that as potency increased or decreased, so did the number of consumers of cannabis presenting in treatment services.

The data presented in the study is convincing. It showed that for every 1% increase in THC strength, around 60 additional people entered treatment. The THC fluctuated  from 8.6% in 2000 to 20.4% in 2004, but by 2015 it had dropped to 15.3%. The treatment data showed the same changes; from 2000 to 2010, first time cannabis presentations had increased four fold from 7 to 26 per 100,000 inhabitants, then dropped again to less than 20 per 100,000 in 2015.

The data in the study showed a delay of 5-7 years from the change in potency to a change in treatment presentations. The reason for this delay makes sense, as it takes time for someone to develop a problematic relationship and recognise they need structured support from a treatment service.

Tom Freeman, a scientist who worked on the study stated that; ‘This is the first study to show an association between changes in potency and cannabis admissions to treatment services. This association persisted after adjusting for client demographics and non-cannabis treatment admissions. These findings support a growing evidence base indicating that higher potency forms of cannabis are linked to greater harms.’

Such a correlation makes a great deal of sense. Behavioral models of addiction state that the more pleasurable an experience is, the more likely it is to be repeated. This simple concept is seen at play here; the more THC in cannabis, the greater the high and therefore the stronger chance of a dependent relationship forming.

The study was conducted in the Netherlands, a country often associated with solid drug policy and positive reform with regards to cannabis. This research however highlights how basic decriminalisation methods are not enough to address the issue of potency. While it is hard to disagree with the benefits of not criminalising every day users, a  lack of regulation appears to not be enough to reduce problematic use as  the cannabis market in the Netherlands remains in the hands of criminals. The KCL study shows how this lack of regulation and control can result in rapid market fluctuations based on consumer choice, availability and growing techniques of the illicit market.

Cannabis potency is a problem that cannot be solved through decriminalisation alone. With its coffee shops and more relaxed drug policies, the Netherlands is often held up as a model to aspire to. This data however suggests such policies are not enough to effectively reduce harm. Changes in potency seems to significantly impact on levels of addiction and dependency and such a correlation would be far better managed through regulation.

Source; Wikimedia

Here in the UK we know that potency has increased significantly. From the Home Office study conducted in
2007 to more recent work undertaken here at Volteface, we know THC levels are consistently high. The Government is becoming increasingly ambivalent on this issue. While more potency data would be welcome, the evidence is reaching a tipping point where the link is beyond questionable.

Liz McCulloch’s recent paper made a convincing case for the rise in cannabis presentations in the UK to be linked to a rise in potency. Her previous work highlighted how public health  services in the UK not effectively  meeting the needs of a rising cannabis cohort. A combination of rising potency and inadequate support poses a problem for the UK.

“Cannabis treatment entries rose significantly from 2004/2005 to 2013/2014, but there had been limited investigation into why this increase had occurred. Plausible and influential explanations are that an expanding treatment offer occurred alongside an expanding cohort of people in need of support around their cannabis use. The evidence suggests increased prevalence in the 1990s to early 2000s, and an increase in high-potency cannabis, led to a significant rise in need for cannabis treatment.”

We now have evidence of increasing cannabis treatment presentations across the UK. There are clear links between THC levels, and addiction. Yet there is still no public policy or even acknowledgement from Government on potency. Public Health England stated; ‘Increased cannabis is a well known and long-standing issue’ and that ‘We are in the process of reviewing whether there is substantive new evidence on cannabis that would warrant its reconsideration by the National Intelligence Network on Health Harms’. Despite such awareness the Government’s latest drug strategy made no mention of the issue and we are seeing budgets for drug treatment (despite evidence of an increase in cannabis presentations) drop across the UK.

The answer to such a problem does not lie with more enforcement as such steps are completely unachievable, both due to the scale of the problem and shrinking police budgets. Similarly doing nothing, or decriminalising possession leaves the market in an unstable state. The THC content in cannabis is the elephant in the room, and it is time to start having open and honest conversations about the its impact.

There are answers to the problems of potency. A legal market with considered regulations, which are based upon evidence and research, could go a long way to address the issue in a number of ways. From taxation based upon THC potency, to clear health warnings and education for consumers, the market can be managed and brought under control. Such models are emerging around the world. In July this year, Justin Trudeau’s Government are launching a regulated cannabis market, which has the opportunity to not only protect young people and consumers, but provide a way of managing the issue of potency. Unfortunately, at present we are left with a Government who do not even acknowledge the issue, never mind think progressively how to solve it. While we wait for action, the time bomb of cannabis potency ticks on…..


Paul North is an Addiction and Treatment Advisor at Volteface. Tweets @Paul_North

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