Designer drugs are multiplying at a worrying rate and increasingly sending users to hospital, a UN-affiliated report has said, calling for international efforts to stem the spread of these substances.

“In recent years, there has been an unprecedented surge in the abuse of new psychoactive substances,” often called “legal highs” or “designer drugs,” the Vienna-based International Narcotics Control Board (INCB) said in its annual report.

“In Europe alone almost one new substance is appearing every week. Previously, between 2000 and 2005 there were an average of five notifications of new substances per year,” added INCB head Raymond Yans.