Substance use and teen pregnancy in the United States: Evidence from the NSDUH 2002-2012

The reduction of adolescent substance use and teen pregnancy are objectives and leading health indicators identified by Healthy People 2020 (U.S. Department of Health and Human Services, 2014). In 2010, underage drinking alone cost the United States an estimated $62 billion in medical care, work loss, and pain and suffering (Pacific Institute, 2011), and teen pregnancy and childbirth are estimated to have added an additional $9 billion in costs to U.S. taxpayers in 2011 (Center for Disease Control and Prevention, 2014). Additionally, both adolescent substance use and pregnancy have been found to place youth at risk for a host of adverse academic, socioeconomic, interpersonal, and health outcomes during adolescence and subsequent developmental stages (Boden, Fergusson, & Horwood, 2008; Grant et al., 2006; Klein, 2005; Paranjothy, Broughton, Adappa, & Fone, 2009; Tapert, Aarons, Sedlar, & Brown, 2001). Simply, substance use and teen pregnancy represent important challenges in terms of the health of the nation and the healthy development of adolescents in the United States. Prior research on adolescent substance use and sexual risk behavior suggests that substance use and teen pregnancy are intertwined. Such research has highlighted the overlapping etiology of substance use with involvement in sexual risk behaviors, such as unprotected sexual intercourse, that place youth at risk for early pregnancy (Hawkins, Catalano, & Arthur, 2002; Resnick et al., 1997). That is, various biological (e.g., genetic, temperamental), intrapersonal (e.g., attitudes, social norms), and ecodevelopmental (e.g., parental support and control, school engagement) factors have been found to conjointly impact the likelihood of substance use and pregnancy-related outcomes (DeLisi & Vaughn, 2014; Prado et al., 2009; Shneyderman & Schwartz, 2012; Vaughn, DeLisi, & Matto, 2013). Epidemiological studies have also documented the comorbidity of health-risk behaviors, including substance use and sexual behaviors that place youth at risk for early pregnancy (Ramrakha, Caspi, Dickson, Moffitt, & Paul, 2000; Salas-Wright, Olate, & Vaughn, 2014a, 2014b; Teplin et al., 2005; Vaughn, Salas-Wright, DeLisi, & Maynard, 2014). Beyond overlapping etiology and comorbidity, evidence also points to the instrumental role of adolescent substance use in sexual behaviors that place youth in jeopardy for early pregnancy (Odgers et al., 2008; Stueve & O'Donnell, 2005). For instance, research suggests that many adolescents use licit and illicit substances prior to intercourse (Fortenberry, 1995) and to facilitate sexual encounters (Bellis et al., 2008). This is noteworthy as intercourse under the influence of alcohol or drugs has been found to be associated with decreased condom use, particularly when the intercourse is unplanned (Poulin, & Graham, 2001). Such findings converge with experimental studies demonstrating the disinhibiting effects and impaired cognitive functioning of alcohol and other substances (Cooper & Orcutt, 1997; Fromme, D'Amico, & Katz, 1999; Poulos, Parker, & Le, 1998), all of which are associated with increased risk for involvement in sexual risk behavior (Dausey & Desai, 2003; Logan, Cole, & Leukefeld, 2002). Evidence also suggests that substance use can contribute to the increased likelihood of sexual risk behavior by means of exposing youth to peer groups endorsing more lenient sexual norms (Huock et al., 2006). It has also been noted that exposure to high-risk peer groups may weaken the relationship of adolescents with prosocial family and peer networks that can serve to protect against involvement in sexual risk behavior (Fergus & Zimmerman, 2005). While a rather extensive body of literature has examined the relationship between adolescent substance use and sexual risk behaviors that place youth at risk for early or unplanned pregnancy (Cook & Clark, 2005; Fortenberry, 1995; Kotchick, Shaffer, Miller, & Forehand, 2001; Leigh, 2002), surprisingly few studies have systematically examined the links between substance use and teen pregnancy. A recent review by Chapman and Wu (2013) identified only a handful of studies focused on adolescent alcohol or drug use prior to and during pregnancy (Amaro, Zuckerman, & Cabral, 1989; Barnet, Duggan, Wilson, & Joffe, 1995; De Genna, Cornelius, & Donovan, 2009; Gilchrist, Hussey, Gillmore, Lohr, & Morrison, 1996; Kaiser & Hays, 2005; Spears, Stein, & Koniak-Griffin, 2010; Morrison, Spencer, & Gilmore, 1998). Results from these investigations suggest that pregnant teens tend to report elevated levels of substance use prior to pregnancy, but report a dramatic decrease in use during pregnancy. This suggests that—while substance use may place youth at risk for early or unintended pregnancy— many youth refrain from use during pregnancy, perhaps due to concerns about the impact of substance use on neonatal health and development (Huizink & Mulder, 2006; Smith et al., 2008). Despite the contributions of previous research, however, several important shortcomings should be noted. First, the aforementioned studies examining substance use prior to and during pregnancy rely exclusively on relatively small and geographically circumscribed samples comprised of pregnant or postpartum youth in predominantly urban areas. These sampling limitations raise important questions about the generalizability of the findings regarding the links between substance use and teen pregnancy. Second, prior studies have tended to report the use of only a limited number of substances (e.g., alcohol, cannabis) and have typically failed to examine substance use disorders. A more nuanced examination of a far-reaching array of substances as well as substance use disorders can shed light on the interrelatedness of substance use and teen pregnancy. Finally, although evidence suggests that both substance use and teen pregnancy vary substantially across the developmental spectrum of adolescence (Costello, Mustillo, Erkanli, Keeler, & Angold, 2003; Kline, 2005), previous research has tended to overlook the developmental complexity in terms of the relationship between substance use and teen pregnancy.