A highly corrosive drug to the body is meth. The initial reaction to the drug can be a euphoric high but it soon results in emotional crashes that cause depression, fear, insomnia and paranoia. This high and low cycle makes users want to take more drugs to forget the negative side effects. This is often referred to as “chasing the high” and results in addiction. In addition to the chemical changes caused by meth, there are many physical changes as well, including the blackening of teeth, abrasions on the skin, and a general hollowness to the face resulting from lack of proper nourishment and sleep.