Major depression is a common mental disorder in children and adolescents. About 20% of the population will experience a depressive episode at least once in their lives. Especially tragic: Suicide is the second leading cause of death among children and adolescents. We want to change that! Our idea: We will create an early-warning system for apps that you don't even notice in everyday life. We simply use the communication via WhatsApp and the smartphone. To get started, we need your help!