Catha Edulis

Catha Edulis also known as Qat is a leaf that has been chewed for centuries in Yemen and parts of east Africa.

Addictions

According to Brian Whitaker in The Guardian:

There's no real evidence that qat is chemically addictive, though people can become psychologically dependent. In that respect it's similar to cannabis: if it turns into a daily habit you'll miss the drug and the social life that goes with it when you suddenly stop.