title: Long-term effects of chronic khat use: impaired inhibitory control.
abstract: So far no studies have systematically looked into the cognitive consequences of khat use. This study compared the ability to inhibit and execute behavioral responses in adult khat users and khat-free controls, matched in terms of age, race, gender distribution, level of intelligence, alcohol and cannabis consumption. Response inhibition and response execution were measured by a stop-signal paradigm. Results show that users and non-users are comparable in terms of response execution but users need significantly more time to inhibit responses to stop signals than non-users.
authors.affiliation: Cognitive Psychology Unit, and Leiden Institute for Brain and Cognition, Leiden University Leiden, Netherlands.
authors.forename: Lorenza S
authors.initials: LS
authors.lastname: Colzato
authors.forename: Manuel J
authors.initials: MJ
authors.lastname: Ruiz
authors.forename: Wery P M
authors.initials: WP
authors.lastname: van den Wildenberg
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Bajo
authors.forename: Bernhard
authors.initials: B
authors.lastname: Hommel