The United States will begin random drug testing of American troops in Iraq. Ten percent of the troops in each unit will be randomly selected each month for a urinalysis. The Persian Gulf has developed a major drug problem over the last decade, as opium and heroin production in Afghanistan skyrocketed. Such large quantities of the drugs are being produced in Afghanistan, that the opium and heroin has become cheap enough for the less affluent population in Iran to get addicted. Gulf State residents are more affluent, and American troops are the most affluent of all. Drug use among American troops has not become a major problem yet, but the local drug suppliers have begun to connect with some of the troops. The testing, which is regularly done when the troops are at their home bases, has kept drug use levels for American military personnel way below those of the civilian population (adjusting for age and education.) But in a war zone, there is more stress, and drugs, both legal and illegal, are one way to deal with it. Troops in high-stress jobs are usually sent home if the stress becomes a problem for them. Combat and drugs dont mix.