Predicting adolescents' persistence, non-persistence, and recent onset of nonmedical use of opioids and stimulants

Abstract

This study sought to distinguish among adolescents who were persistent, non-persistent, or recent onset nonmedical users of prescription opioids and stimulants (respondents' ages ranged from 12–17 years, N = 126,764). The multinomial logistic regression analyses of combined data from the 2003 through 2009 National Survey of Drug Use and Health were used to investigate the association of respondents' sex, age, family income, race, parental status, population density, and user status (persistent, non-persistent, recent onset) on common illicit substances (cigarettes, alcohol, marijuana, and inhalants) with opioid and stimulant use. The odds of nonmedical opioid and stimulant use were significantly greater for females than males, and increased with age. Results were mixed for income, race, and parental status. Population density was largely unrelated to nonmedical use. Persistent nonmedical users of common illicit substances, especially marijuana and inhalants, were at greatest risk for nonmedical opioid and stimulant use. Non-persistent use of common illicit substances was a strong predictor of both non-persistent opioid and stimulant use. Recent onset of common substance use predicted recent onset of prescription opioid and stimulant use. Results indicate that persistence may be related to polysubstance use involving prescription opioids and stimulants, supporting efforts to investigate the underlying causes of polysubstance use.

Introduction

Over the past several years, adolescents' increasing nonmedical use of opioids and stimulants has become a major concern in the US (Johnston, 2009), with millions of 12–18 year olds using them annually (Substance Abuse and Mental Health Services Administration, 2009). Reflecting the danger of improper use of prescription medications, emergency room visits involving opioid use rose to an estimated 111% between 2004 and 2008 (Substance Abuse and Mental Health Services Administration, 2010). Further societal costs have been noted in both a dramatic increase of opioid-motivated robberies of pharmacies between 2006 and 2010 (Hawley, 2011) and an estimated $150 million of duplicate prescriptions billed to Medicare Part D in 2008 (US Government Accountability Office, 2011). Despite mounting concern, nonmedical use of prescription drugs such as opioids and stimulants remains very much understudied.

Numerous studies have established relationships between nonmedical use or misuse of prescription opioids, stimulants, and other substances (Back et al., 2010, Boyd et al., 2009, Ford, 2009, Goldsworthy and Mayhorn, 2009, Levine and Coupey, 2009, McCabe, Boyd, Cranford and Teter, 2009, McCauley et al., 2010, Schepis and Krishnan-Sarin, 2009, Wu et al., 2008), though many do not classify users into meaningful subtypes (McCabe, Boyd, & Teter, 2009). As research has suggested, there is substantial heterogeneity among nonmedical users of prescription drugs across various dimensions, including motive (Boyd et al., 2006, McCabe, Boyd and Teter, 2009, McCabe, Cranford, Boyd and Teter, 2007, Teter et al., 2005, Teter et al., 2006), route of drug administration, (Compton and Volkow, 2006, McCabe, Boyd and Teter, 2009, McCabe, Cranford, Boyd and Teter, 2007, Teter et al., 2005), co-ingestion, (Compton and Volkow, 2006, McCabe, Boyd and Teter, 2009, McCabe, Cranford and Boyd, 2006) and time of onset (Dowling, Storr, & Chilcoat, 2006). Better identification of user subtypes may help identify those at greatest risk, the correlates of those risks, and the consequences the risks carry, better shaping our understanding and the efficacy of prevention efforts.

Research by Dowling et al. (2006) subtyped users by time of onset, categorizing them into recent onset (< 24 months prior to interview) and persistent users (onset beginning 24 + months prior, with some use indicated within the past year). More recently, other researchers have identified experimentation as a major reason for use of opioids and stimulants by adolescents (McCabe, Boyd, Cranford and Teter, 2009, Teter et al., 2006) and college students (McCabe, Boyd and Teter, 2009, McCabe, Cranford, Boyd and Teter, 2007, Teter et al., 2006).

Numerous studies also have examined demographics related to nonmedical use of prescription drugs. Studies commonly find females more prone to nonmedical use than males (Dowling et al., 2006, Schepis and Krishnan-Sarin, 2008, Teter et al., 2003, Wu et al., 2008). Not surprisingly, the odds of lifetime nonmedical use increase with age as well (Dowling et al., 2006, Havens et al., 2011, Wu et al., 2008). Results have been less consistent for other demographic variables. Some studies have found nonmedical use less common among lower income categories than higher ones (Wu et al., 2010, Wu et al., 2008), but other researchers have come to the opposite conclusion or found no differences (McCabe, Teter and Boyd, 2006, Simoni-Wastila et al., 2008). Similarly mixed results have been observed with race (Daniulaityte et al., 2009, McCabe et al., 2008, McCabe, West, Morales, Cranford and Boyd, 2007, Simoni-Wastila et al., 2008, Wu et al., 2008, Wu et al., 2010), and county type (Havens et al., 2011, McCabe, Boyd and Teter, 2005, McCabe, Teter, Boyd, Knight and Wechsler, 2005, Simoni-Wastila et al., 2008, Wu et al., 2008). Few studies have considered parental status (Havens et al., 2011, Hemovich and Crano, 2009, Hemovich et al., 2011, Schepis and Krishnan-Sarin, 2008), but those that have suggest adolescents from dual parent households are at less risk for substance use than those from other types of family structures.

Because many adolescents discontinue substance use after a short period of experimentation (Botvin & Griffin, 2007), the present study sought to investigate whether adolescents who discontinued the use of a common illicit substance (marijuana, inhalants, etc.) are differentially at risk for use of other drugs relative to those who persist with use, who have recently begun using, or who never have used.

Persistent use of common illicit substances was expected to be associated with nonmedical opioid or stimulant use. Given the consistency of results found in other studies, it was anticipated that females would be more likely to use than males, that odds of use would increase with age, and that adolescents from dual parent households would be at less risk than those from single parent or absent parent households across all categories. No predictions were made with respect to other demographic variables due to the mixed results noted in earlier studies. Differences between persistent, non-persistent, and recent onset users were expected, and though no specific predictions about strength of relationships were made, it is reasonable to expect that polysubstance use would be more likely when nonmedical use of either stimulants or opioids was persistent, rather than transitory.