Is the increase in 'super strength skunk' in Britain a reason to legalise cannabis?
This new study is scientists confirming what we already know. There is nothing new here - it has been clear for 30 years that THC levels in street cannabis are rising.
The first driver is prohibition. As with alcohol prohibition, more concentrated versions of the drug are promoted.
The second is improved growing techniques. This means inhaling less harmful smoke for the same effect.
Under prohibition, consumers have no choice, no labelling, and no quality control. The answer is...