[The concept of "gateway drug"]

To develop drug abuse prevention for adolescents in Japan, the author reviewed concepts of "gateway drug" and "stepping-stone hypothesis". Firstly, results obtained from high school students in New York State (Kandel, D., 1975) were introduced as a standard model of "stepping-stone hypothesis". Secondly, results obtained from serious drug abusers in New York City (Golub, A. et al., 1994) were introduced as an example that shows the importance of defining clearly which cohort a study refers to when we use "gateway drug". Thirdly, results of a junior high school students survey in Japan were introduced and discussed to consider whether alcohol and cigarette for junior high school students in Japan are "gateway drugs" to solvent. The author concluded: 1) that cigarette smoking in junior high school students in Japan has a strong relationship with solvent inhalation, and 2) that drinking alcohol, however, depends on the presence of adults. Lastly, the author emphasized the need for doing more research on drug abuse in Japan.