Certain sub-populations of adolescents, such as racial and ethnic minorities and street-involved youth, may be particularly vulnerable to barriers to treatment services.

Research suggests that there may be some differences in SUD treatment utilization based on race and ethnicity. Research by Wu and colleagues (2002; 2003) examined data from the National Household Survey on Drug Abuse for racial and ethnic differences in service utilization. Even after controlling for severity of alcohol treatment need, white adolescents were more likely to receive alcohol treatment services than minority adolescents (Wu et al., 2002). Findings of racial/ethnic differences in utilization are less clear for adolescents who use illicit drugs. Although Wu et al. (2003) found initial differences in receiving treatment by race and ethnicity, differences in indicators of problem severity and treatment need accounted for racial and ethnic differences in utilization.

State-level studies have also found differences in utilization. Disparities in utilization of Medicaid-funded SUD treatment services and age of first treatment service between black adolescents and white adolescents have been documented in Tennessee (Heflinger et al., 2006). In San Diego County, California, Garland et al. (2005) found racial and ethnic differences in utilization of outpatient mental health/SUD services, including lower utilization among African American and Asian American/Pacific Islander adolescents.

One population of adolescents who are particularly vulnerable to both SUDs and barriers to treatment are street-involved or homeless youth (Mallett et al., 2005). Rates of substance use among street-involved youth are much higher than among adolescents with stable housing (Greene et al., 1997). Studies have shown low rates of service utilization (De Rosa et al., 1999; Slesnick et al., 2001). In one study of Canadian street-involved youth who attempted to access treatment, about 22% were unable to access services and 21% reported challenges in access although they were ultimately successful in obtaining services (Hadland et al., 2009); the most widely cited barrier was lengthy waiting lists. Street-involved youth may fear that treatment-seeking will result in stigmatization and may face substantial pressures from other street-involved peers to not seek treatment (Brands et al., 2005).