The randomly selected drug tests carried out at the upper secondary schools in Karlskrona are voluntary. But after SVT Nyheter's review after a high-profile post on social media, it is clear that some students perceive them as forced - which would be illegal.

Guardians must pass drug tests

According to the head of operations for the upper secondary schools, the students are informed on a number of occasions during schooling that the tests are voluntary. Among other things, through a form that guardians must sign that their child may be drug tested.

"It's a challenge that information doesn't necessarily turn into knowledge," says Victor Lindberg Karlsson, operations manager for the upper secondary schools.

"You can always screw up the set-up and we'll take that to heart," he says.