Journal of Health and Social Behavior 51(2) 153 –167 © American Sociological Association 2010

The developmental period immediately after high school is characterized by increases in rates of heavy episodic drinking, marijuana use, and ciga-rette smoking (Arnett 2005; Bachman et al. 1997; White et al. 2006). An important source of influ-ence on substance use during this developmental period is romantic relationships. Romantic rela-tionship status, stability, and quality, as well as the partner’s own substance use, have been found to be related to substance use and abuse and other forms of problem behavior, even after adjusting for prior patterns of behavior (Bachman et al. 1997; Rhule-Louie and McMahon 2007). Prior studies, how-ever, have not fully accounted for the heterogeneity of relationship status in the immediate post-high school period, failing to distinguish statuses of marriage, cohabitation without marriage, dating without cohabitation, and being truly single. Also, prior studies have not tested for the interaction 1University of Washingto