“…Another study reported the association between the development of oral cancer and chronic khat use (Soufi, Kameswaran, & Malatani, 1991). Previous studies described the addictive properties of khat and the presence of a range of dependence-related symptoms among Yemenis and UK and Australian populations of African provenance (Kassim, Croucher, & Al'Absi, 2013;Nakajima, Hoffman, & Al'Absi, 2017;Young, Butt, Hersi, Tohow, & Mohamed, 2016). In addition, a 2017 study carried out in Ethiopia indicated the psychological severity of khat addiction in polysubstance users (Manzar et al, 2018).…”