Worldwide phenomenon

Chewing leaves from the khat plant (Catha Edulis) in Eastern Africa and in the south west of the Arabian Peninsula is a tradition dating back hundreds of years. During the last ten years, mainly because of the Somali diaspora, chewing khat has turned into a worldwide phenomenon broadening to ethnic communities in the rest of the world, such as in North America, Great Britain, and the Netherlands.

Khat, a “natural” amphetamine

Khat has gained the reputation as a “natural amphetamine” because cathine and cathinone, the two main the active ingredients, are similar in structure and pharmacological activity to amphetamines. Chewing khat eases exhaustion, increase alertness and self-esteem, decrease hunger, induce euphoria and feelings of well-being. However, once the positive acute effects vanish, users undergo feelings of exhaustion, sleeplessness, apathy, depression, lethargy, mental fatigue, and concentration difficulties.

Long-term cognitive impairments in khat users

Several studies from our lab have shown that the chronic (i.e. daily) long-term use of khat is associated with impairments in stopping on time, in cognitive flexibility (the ability to adapt and restructure cognitive representations in response to changing situational demands) and in the monitoring of information in working memory.

Acute Cognitive Effects

For the first time, in our recent study published in Frontiers in Human Neuroscience we explored how acute khat use affects the ability to ignore irrelevant information on a computer screen. We found that, while using khat, users were less distracted from the irrelevant information than nonusers.

Self-medication hypothesis of khat use?

Our results may be consistent with a self-medication hypothesis of khat consumption. It is not to exclude that khat users may have a pre-existing predisposition to being distracted and, thus, they may have learned to use khat in order to reverse and improve their ability of suppressing irrelevant information.