Highly concentrated varieties of cannabis could be added to the category of "hard" drugs because of the risk of addiction.

A Dutch commission has found that hashish and marijuana on sale in the Netherlands contain around 18 percent of THC (psychoactive substance tetrahydrocarbinol) and should be considered as addictive as heroin and cocaine given that 15 percent is the threshold.  

"I've been very worried for years about the THC concentration, especially if it is so high.. The addictive consequences are much stronger and severe. Clearly this is a worrying development," said Health Minister Edith Schippers.

Note that last month the Dutch government finalised the plan to turn coffee shops into private clubs for locals.

Source: Reuters.com