A campaign by Rotterdam city council to draw attention to the impact of illegal drugs has stimulated a different sort of crime this week, as students and others stole street signs referencing cocaine, ketamine, and MDMA.

Council officials decided to “rename” 11 city street signs using drug references so, for example, Coolsingel became Cokesingel, the Ketenstraat became Ketastraat and Laan op Zuid became Lijn (line) op Zuid.

They hoped to stimulate discussion about the use of illegal drugs on wider society and the boards contain extra information about drugs use. Cokesingel, for example, states that “63,000 lines of cocaine a day have an impact on the city”. MDMA Laan (Emmalaan) points out that 28 drugs labs were dismantled in Rotterdam last year.

But within hours of the first signs being put up, they began disappearing, local broadcaster Rijnland reported. West-Snuifkade is now hanging on the wall in a student house and a group of 20-somethings told the broadcaster they were on the prowl looking for Ketastraat as a trophy.

Experts have also criticised the campaign. Psychologist Wendy Oude Velthuis said on social media this sort of approach usually has the opposite effect. “By focusing attention on drugs related names and statistics about usage, the council is unwittingly strengthening the normalisation of drugs in the city,” she said.

The street sign project is part of a wider campaign to highlight the impact of the drugs industry across the port city in the coming weeks.

“We want to give users a broader view of their own reality,” says city law and order chief Pascal Lansink-Bastemeijer. “Users must realise that drugs have a dark side. We hope [this campaign] will stimulate discussion and de-normalise drugs use.”

Meanwhile, a council spokesman told Rijnmond he was not surprised the boards had been stolen so quickly. “We expected it,” he said. “But we would ask the thieves to take note of the message and talk about it.”

He declined to say if the boards would be replaced.