In places that opened up commercial markets for cannabis, such as the US and Canada, researchers saw more users and increases in drug potency. More people also visited hospital with psychosis and other mental health issues linked to the drug, they found.

Where cannabis was decriminalised in Europe, Africa, Oceania and Asia, there was little evidence of any change in usage or psychiatric illness. The experience was similar in Uruguay, where cannabis has been legalised but is tightly controlled by the state.

So unfettered and unregulated capitalism causes mental health issues but we already knew that but always nice to see another data point.