One of the most popular stereotypes about drug use is that it is more prevalent among the poor. In fact, a lack of money—in itself—does not seem to be associated with drug use. Empirical research has found, however, that in the United States, a number of attitudes, behaviors, and conditions linked to drug use also are linked to poverty, thus creating a situation that encompasses more than a lack of money. The study of poverty and drugs in the United States is complicated by the complexity of poverty as a conceptual category and by methodological problems in the measurement of drug use.

Merriam-Webster's Collegiate Dictionary, Tenth Edition defines poverty as "the state of one who lacks a usual or socially acceptable amount of money or material possessions." The sociological definition focuses on the relational aspect of poverty: Poor people are...