Ecstasy pills are becoming stronger and cocaine sold on the streets is more pure, according to a new report by the addiction centre Trimbos Institute.

The institute bases its claim on tests carried out on 12,000 drug samples in 2017. The researchers found the amount of mdma – the active ingredient – in ecstasy pills had gone up from an average 120 milligrams in 2013 to 167 milligrams last year.

When it comes to cocaine, in 2014, just 59% of the powder was made up of the actual drug, but this rose to an average of 68% last year.

Spokesman Daan van der Gouwe said it is difficult to say why ecstasy pills have become stronger but the cheapness of the drug is likely to be the deciding factor. ‘It costs peanuts’, so producers are unlikely to worry about how much they use, he told broadcaster NOS.

He describes the development as worrying. ‘The stronger the pill, the stronger the effect and that can cause problems for some people,’ he said.