Inhalants are a critical, under-studied substance used by young adolescents in the United States (U.S.). Despite the serious negative consequences that can accompany use (most notably neuropsychological damage) the topic of inhalants has been neglected by clinicians and prevention scientists, particularly in comparison to other drugs. The present research focused on the etiology of U.S. adolescent inhalant use in two ways, both of which utilized large, nationally representative data sets for secondary data analysis. Study I examined long-terms trends in inhalant use prevalence rates and changing proportions of gender and ethnic groups among lifetime inhalant users. Study I also evaluated the effects of policies aimed at other drugs, including regional "three strikes laws" and national methamphetamine laws, on changing inhalant use prevalence rates among twelfth graders. Inhalant use increased during the early-1990s but has declined from the mid-1990s to the present day; lifetime inhalant users have increasingly become female and non-White. Importantly, "three strikes laws" and a national methamphetamine law were related to increases in annual inhalant use rates for twelfth graders. Study II evaluated the applicability of Self-Determination Theory (SDT)-related constructs, namely self-perceived autonomy, competence and parental relatedness, to concurrent and prospective inhalant use. Competence was consistently related to inhalant use and inhalant use severity; parental relatedness was related to concurrent but not prospective use and use severity. The findings from both studies are discussed in terms of their commonalities and differences, implications for clinicians and prevention scientists, overall strengths and limitations, and directions for future inhalant use research.