Ethics Approval
The study was performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki and its later amendments. We obtained ethical approval and research permits from the ethics committee of Bielefeld University in Germany and from the University of Dar es Salaam and all relevant authorities in Tanzania. Research assistants were trained and instructed to refer participating students who exhibited marked psychological distress during the interview or who reported serious ongoing emotional or physical abuse that exceeded culturally acceptable levels to the study psychologist. The study psychologist conducted a follow-up interview and determined whether to involve guidance counsellors, parents, school administrators, or authorities on a case-by-case basis. There was a small number of severe cases of persistent abuse by teachers.