The youth mental health crisis: Quasi-experimental evidence on the role of school closures.

During the COVID-19 pandemic, the youth mental health crisis has reached unprecedented levels. To which extent school closures, one of the most heavily debated pandemic measures, have contributed to or even caused this crisis is largely unknown. We seek to narrow this blind spot, by combining quasi-experimental variation in school closure and reopening strategies across the German federal states at the onset of the pandemic with nationwide, population-based survey data on youth mental health and high-frequency data from the largest crisis helpline.