Christin Scheiner, Andrea Daunke, Alexandra Seidel, Sabrina Mittermeier, Marcel Romanos, Michael Kölch, Arne Buerger

• Background Chronic stress is detrimental to health, and children and young people have had to cope with significantly more stress since the start of the COVID-19 pandemic. In particular, stress at school and in relation to learning is a major problem in this age group. Studies in Germany have indicated that the pandemic has led to a reduced quality of life (QoL) and an increased risk for psychiatric disorders in children and adolescents. Schools are an ideal setting for interventions against stress, which is one of the strongest predictors forBackground Chronic stress is detrimental to health, and children and young people have had to cope with significantly more stress since the start of the COVID-19 pandemic. In particular, stress at school and in relation to learning is a major problem in this age group. Studies in Germany have indicated that the pandemic has led to a reduced quality of life (QoL) and an increased risk for psychiatric disorders in children and adolescents. Schools are an ideal setting for interventions against stress, which is one of the strongest predictors for the development of psychosocial problems. The present study seeks to address stress by means of a short prevention training programme in schools, including emotion regulation, mindfulness, and self-compassion. In addition to information material for self-study, students should have the opportunity to actively deal with the topic of stress and develop coping strategies within a short space of time. In contrast to very long stress reduction programmes that often last several weeks, the programme is delivered in just 90 min. Methods The effectiveness of the short and economical prevention programme LessStress will be examined in a cluster-randomised controlled trial (RCT) encompassing 1894 students. At several measurement time points, students from two groups (intervention and control) will be asked about their subjectively perceived stress levels, among other aspects. Due to the clustered nature of the data, mainly multilevel analyses will be performed. Discussion In Germany, there are no nationwide universal prevention programmes for students against stress in schools, and this gap has become more evident since the outbreak of the pandemic. Universal stress prevention in schools may be a starting point to promote resilience. By dealing with stress in a healthy way, mental health can be strengthened and maintained. Moreover, to reach at-risk students at an early stage, we advocate for a stronger networking between child psychiatry and schools.…