A reader writes:
Your reader makes a very impassioned case for qat in terms of its properties as a drug, but the problem with qat is not really that it has particularly ill effects on the body and mind (although it is pretty addictive, which is cause for concern). The big problem is environmental; the plant has practically destroyed Yemen. Around 40% of Yemen's water supply goes into growing it, and that number is going up even as the water supply dwindles. Yemen today is pretty much desiccated, yet continues to pour large quantities of water into qat production, at the expense of food agriculture, industry and availability for personal use.