A comprehensive bibliometric analysis of Catha edulis (Vahl) Endli (Khat) research (1961–2021)

Bulletin of the National Research Centre

Table 4 Keywords’ co-occurrence and important topics and major research themes

Clusters No	Important topics and major research themes	Color of the cluster*
1	Phytochemistry, botany and pharmacology of Khat	Green
2	Addiction, concurrent use of other drugs, survey-based studies, sex difference	Red
3	Case reports, clinical studies, pathology	Blue
4	Case–control studies	Yellow

*The color of the clusters is based on the visualization performed using VOSviewer as depicted in Fig. 10