Danes lead EU cannabis league

Levels also stand high at around 40 percent in France, Spain, the UK and the Czech Republic but bottom out at under 10 percent in Cyprus, Bulgaria, Malta and Romania (3%). Canada is the global leader on 58.6 percent with the US on 49 percent.

A gram of herbal cannabis costs around €1.40 in Spain but €21.50 in Norway, with most countries "retailing" the illegal drug in the €5-to-€11 range, and with prices having stabilised or fallen across Europe since 1996.

The highest concentration of of tetrahydrocannabinol (THC) - the active ingredient in cannabis - tends to be in the Netherlands at over 20 percent content while Portugal and Italy scrape the bottom of the THC table at less than three percent.

The 700-page survey explores the use of cannabis in Europe from the early 19th century, when medical treatises such as the 1839 Irish text "On the Preparations of the Indian Hemp or Gunjah" first popularised the drug.

It notes that while THC can be used to treat convulsive disorders such as spasticity, it can also lead to infant disorders when smoked by pregnant women and aggravate the onset on schizophrenia in teenagers.

The EMCDDA paints a picture of a divergent regulatory landscape in the EU, with decriminalisation trends in Portugal and Luxembourg but toughening measures in Denmark, Italy and the Netherlands.

"Over 13 million Europeans have consumed it in the past month. Globally, nearly 50,000 tonnes of cannabis herb or resin are produced for consumption every year," the survey says. "Little wonder, then, that cannabis has become a controversial cultural phenomenon."