Does a mindfulness-augmented version of the German Strengthening Families Program reduce substance use in adolescents? Study protocol for a randomized controlled trial oleh Nicolas Arnaud, Christiane Baldus, Léa Josette Laurenz, Sonja Bröning, Maja Brandt, Sabrina Kunze, Maria Austermann, Linda Zimmermann, Anne Daubmann, Rainer Thomasius, the IMAC-Mind Consortium