There are several compelling reasons for reforming the law around cannabis (Photo credit should read MUJAHID SAFODIEN/AFP/Getty Images).

Those who still believe in the war on drugs are concerned that the legalisation of medical cannabis will lead to the legalisation of recreational cannabis.

Insofar as there is growing momentum for drug reform, they are right to be worried about a ‘slippery slope’ of liberalisation but the case for (re)legalising marijuana rests on a different set of arguments to those put forward during the Billy Caldwell case.

There is no campaign for other licensed medicines to be sold over the counter like alcohol. Cannabis is different.

There are several compelling reasons for reform. Legalisation would allow the police to focus on more serious crime. Wiping out the black market would make it harder for children to get hold of the drug.




The government would raise significant tax revenue. In a recent report for the Institute of Economic Affairs, I estimated that around 255 tonnes of cannabis were consumed in Britain last year at a cost of £2.6billion.

If this market were brought into the legitimate economy, sales taxes alone could raise £690million. New streams of income tax, VAT and business taxes would yield several hundred millions of pounds more. Meanwhile, lower prices would leave cannabis consumers with more money to spend in other parts of the economy.

But perhaps the most pressing reason for reform is to protect the mental health of those who use cannabis. Until around 10 years ago, it was considered to be a relatively ‘soft’ drug. Tony Blair’s government rescheduled it into Class C in 2004 and there was significant political support for full legalisation.

But by the time Gordon Brown returned it to Class B in 2008, public perception of cannabis has begun to change. It was increasingly associated with dependency, psychosis and schizophrenia.

Cannabis underwent an image change because cannabis itself had changed. Sinsemilla – better known as ‘skunk’ – has taken over the market.

This is significant because skunk is typically high in tetrahydrocannabinol (THC), which is associated with psychosis, and low in the non-intoxicating antipsychotic drug cannabidiol (CBD). THC is the main psychoactive substance in cannabis. It makes the user feel stoned, but it can also cause side effects such as paranoia which can be alleviated by CBD.

With high levels of THC and low levels of CBD, skunk poses a greater threat to mental health than the cannabis of old. Although the number of cannabis users fell by a third between 2006 and 2014, demand for treatment of cannabis-related mental health problems increased by more than 50%.

The rise in cannabis-related mental health harm is alarming, but it makes the case for legalisation stronger, not weaker. Opposing legalisation on the grounds that skunk has taken over the market is like opposing the end of alcohol prohibition because moonshine had taken over the market.

Dangerous, high-strength moonshine virtually disappeared after alcohol was re-legalised in the USA in 1933 and the same would happen to the worst strains of sinsemilla if cannabis were re-legalised and regulated.

High THC strains do not necessarily exist due to consumer demand. Black markets tend to suit sellers rather than buyers. The shift towards skunk in Britain came about because the illicit market moved away from importing cannabis to growing it indoors with hydroponic lights.



Cross-breeding of plants then created more potent strains with high levels of THC. Those who grew it did not care how little CBD was in it. They just wanted it to be ‘strong’.

Capping THC levels and mandating minimum CBD levels would greatly reduce the risk to mental health. This can only be done if the product is legal and regulated.

The belief that cannabis consumption can be suppressed through prohibition has been tested to destruction. Canada and a growing number of US states have successfully legalised the product. Now it is our turn.

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