The Trimbos drug expertise institute said on Thursday it is very concerned that the amount of the active ingredient MDMA in an ecstasy pill has gone up by 50% over the past few years.

A few years ago there was an average of 80 milligrammes in a single pill, but this has now gone up to around 120 milligrammes, Trimbos said in a statement.

The institute says the increase in MDMA content is worrying because this leads to a higher risk of heart problems, liver problems and psychotic attacks.

Trimbos is also critical of the ‘light-hearted’ approach in recent discussions about the risks of using ecstasy.

While ecstasy is rarely addictive there are risks attached to its use and every year several people in the Netherlands die as a direct result of taking the drug, the institute said.