Corrigendum: Prevalence of Novel Psychoactive Substance (NPS) Use in Patients Admitted to Drug Detoxification Treatment - Specka, Michael; Kuhlmann, Thomas; Sawazki, Jürgen; Bonnet, Udo; Steinert, Renate; Cybulska-Rycicki, Monika; Eich, Helmut; Zeiske, Benita; Niedersteberg, Antje; Schaaf, Luzia; Scherbaum, Norbert (Frontiers in Psychiatry, 2021)