Khat Use Is Associated with Impaired Working Memory and Cognitive Flexibility Colzato, Lorenza S. ; Ruiz, Manuel J. ; van den Wildenberg, Wery P. M. ; Hommel, Bernhard Abstract Publication: PLoS ONE Pub Date: June 2011 DOI: 10.1371/journal.pone.0020602 Bibcode: 2011PLoSO...620602C