Khat Use Patterns, Associated Features, and Psychological Problems in a Khat-Treatment-Seeking Student Sample of Jimma University, Southwestern Ethiopia oleh Mekdem Tesfamichael Hassen, Matiwos Soboka, Marina Widmann, Marina Widmann, Lucas Keller, Anja C. Zeller, Anja C. Zeller, Natascha Büchele, Eva Barnewitz, Eva Barnewitz, Yimenu Yitayih, Sabine Schiller, Jael Senger, Kristina Adorjan, Kristina Adorjan, Kristina Adorjan, Michael Odenwald, Michael Odenwald