Emerging research suggests that White youth are more likely to show continuity Immethridine hydrobromide of alcohol Immethridine hydrobromide use in the year following drinking onset compared to Black youth. by race: “no use ” “alcohol only ” and Immethridine hydrobromide “polydrug use.” Although similar labels describe the profiles the probability of endorsing use of a particular substance for a given profile differed by race precluding direct comparison. Latent transition analyses of five annual waves covering ages 13-17 indicated that an intermittent pattern of use (e.g. use in one year but not the next) was relatively low at all ages among White girls but among Black girls an intermittent pattern of use began to decline at age 15. Among Black girls conduct problems at age 12 predicted substance using profiles at age 13 whereas among White girls intentions to use alcohol and cigarettes at age 12 predicted substance using profiles at age 13. Racial differences in girls’ substance use profiles suggest the potential utility of culturally-tailored interventions that focus on differences in risk for specific substances and relatively distinct early patterns of use. Keywords: adolescent females alcohol cigarette marijuana race/ethnicity conduct problems National survey data indicate racial/ethnic differences in adolescent substance use such that White adolescents report higher rates of alcohol cigarette and marijuana use compared to Black youth (Johnston et al. 2010 Substance Abuse and Mental Health Services Administration 2011 In the context of these racial/ethnic differences there also has been a narrowing gender gap in rates of substance use with females catching up to males in recent years (Johnston et al. 2010 The increasing prevalence of substance use among adolescent females is alarming because females are at greater risk for certain types of substance-related harm compared to males (Institute of Medicine 2004 Nolen-Hoeksema 2004 Specifically substance using females compared to males may be at greater risk for dating violence (e.g. Foshee et al. 2001 risky sexual behavior and sexually transmitted disease (e.g. Hutton et al. 2008 and accelerated progression to nicotine dependence (DiFranza et al. 2002 Greater risk for harm among females may be due for example to greater effects of a Immethridine hydrobromide substance at similar doses (e.g. alcohol) and contexts of use (e.g. with a substance-using romantic partner) which may facilitate the occurrence of substance-related harm relative to males (Nolen-Hoeksema 2004 In the context of such risks and the need to understand racial/ethnic differences in patterns and predictors of substance use this study examined age-to-age changes in alcohol cigarette and marijuana use during adolescence in White and Black girls. Prototypical profiles of adolescent substance use (e.g. “alcohol only ” “alcohol and tobacco use”) have been identified in cross-sectional Keratin 16 antibody data using latent class analysis (LCA) (e.g. Lanza & Immethridine hydrobromide Collins 2002 Reboussin Hubbard & Ialongo 2007 Dauber et al. 2009 Lanza Patrick & Maggs 2010 Cleveland et al. 2010 LCA is a person-centered approach to identifying latent classes or common profiles of substance use that reflect relatively distinct subgroups (Collins & Lanza 2010 When alcohol cigarette and marijuana use have been used to derive substance use profiles in adolescents 4 profiles have been identified such as “no use ” “alcohol only ” “cigarette only ” and “alcohol cigarette and marijuana use” (e.g. Lanza et al. 2010 Cleveland et al. 2010 Differences across studies in the number and nature of the substance use profiles that have been identified may reflect for example differences in sample age range recruitment method and differences in the items (e.g. consumption of 5+ drinks per occasion) and time frames used. Some studies have characterized substance use profiles in specific race/ethnic groups using LCA (e.g. Hispanic youth: Maldonado-Molina et al. 2007 Black youth: Reboussin et al. 2007 One cross-sectional study contrasted White and Black adolescent females (ages 13-19) on profiles based only on alcohol involvement (Dauber et al. 2009 and found four subtypes in White females (abstainers experimenters moderate drinkers heavy.