There is a general suspicion that stress and stress-related psychological disorders is growing in highschool students in Sweden. Mindfulness is a well researched therapeutical method for treating stress-related disorders. This study will first collect data on stress-related psychological symptoms by several well-validated surveys. The surveys will be made twice with 8 weeks in between to examine variability. After the second survey the population of highschool students will be randomly assigned to web-based mindfulness intervention, music relaxation intervention or control group. A third survey will be conducted after eight weeks of intervention and before and after an external stressor.