Research on psychiatric comorbidity among opiate and cocaine addicts has consistently found African-Americans to report fewer symptoms of anxiety and affective disorders than Whites. The current article reviews the research on these racial differences, evaluates various interpretations of these differences, and discusses the limitations of past research. It is concluded that Whites and African-American addicts differ in their underlying reasons for abusing drugs. Drug addiction among Whites appears to be related largely to psychopathology, whereas Black drug abuse is best understood in terms of social and environmental factors. Treatment implications are also discussed.