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Article Excerpt
"Abuse of prescription drugs to surpass illicit drug abuse, says INCB"
--INCB PRESS RELEASE, 2007
The above headline topped a recent International Narcotics Control Board (INCB) Press Release (2007) that went on to say that the "abuse of prescription drugs has already surpassed abuse of traditional illicit drugs such as heroin and cocaine in some parts of the world", referring to the United States (U.S.) as the outstanding example. Recent commentaries in key scientific journals have suggested a paradigm shift (Fischer & Rehm, 2007), with prescription opioid (PO) misuse (1) increasingly outpacing or replacing misuse of heroin, considered one of the dominant illicit drugs for many decades (Courtwright, 1982; Musto, 1987). Even though the social history of several illicit drugs (e.g., heroin, cocaine) began with the non-medical uses of what originally existed as a pharmaceutical drug (ibid.), prescription drug misuse in many--science and policy--contexts has long lived a rather neglected existence in the shadows of the licit and illicit drugs. For example, the most recent Canadian Addiction Survey (CAS) did not include any question item on prescription drug misuse (Adlaf, Begin, & Sawka, 2005), and the Canadian Social Costs of Substance Abuse study also did not include PO misuse as an explicit part of its estimations (Rehm, Baliunas, Brochu, Fischer, Gnam, Patra, et al., 2006).
This article will examine available data on the epidemiology; morbidity, mortality and other harm; sourcing routes; and the challenge of interventions related to PO misuse available from North America (i.e., mainly the U.S.).
Epidemiology of PO misuse
While the misuse of opioid-pharmaceuticals can be traced back more than a century, (Courtwright, 1982; Musto, 1987), the phenomenon of PO misuse at the beginning of the 21st century is distinct due to "the scale, range and growth of the problem"(Compton & Volkow, 2006, p. 103). There is evidence of substantial increases in therapeutic PO use in many regions, and of PO misuse for countries around the world. However, the country with by far the most systematic data available especially for the latter is the U.S., thus defining a primary focus on U.S. (and some Canadian) data for this review. The considerable divergence in available data between the U.S. and the rest of the world is likely driven by several factors, yet probably relate to the unique health research and substance misuse control infrastructure in that country.
According to recent epidemiological (national household survey) data, 4.7% (i.e., 11 million) U.S. household residents (over the age of 12) reported PO misuse in 2002 (SAMSHA, 2003; Compton & Volkow, 2006). Furthermore, about one in eight (13.7%) of past year PO misusers met the symptom criteria of a Diagnostic and Statistical Manual of Mental Disorder, 4th edition (DSM-IV) opioid use disorder, compared to 53% for heroin, 16.7% for marijuana and 11.6% for alcohol (ibid.). The National Survey on Drug Use and Health (NSDUH) documented that the "annual incidence of opioid analgesic abuse increased from 628,000 initiates in 1990 to 2.4 million initiates in 2001", thus almost quadrupling within a decade (ibid.) and exceeding incidence values for all other major drug categories (e.g., tranquilizers, stimulants, sedatives) in 2001. For comparison: the existing heroin addict population in the U.S. has typically been estimated in size to be around one million-less than half the number of incident cases, and less than a tenth of the estimated prevalent cases of PO misuse in 2002 (National Institutes of Health, 1998; Office of National Drug Control Policy, 2001). For a different viewpoint, Cicero and colleagues surveyed several hundred key informants (e.g., addiction treatment specialists and researchers) with regard to the prevalence of PO misuse in 208 (21.4%) of the U.S." 973 three-digit zip codes. Respondents reported that Oxycodone and Hydrocodone misuse cases occurred in about 60% and 50% of the zip codes, respectively, surveyed between 2002 and 2004, and that the proportion of zip codes reporting at least five cases of misuse in that period had increased substantially (Cicero, Inciardi, & Munoz, 2005).
Besides indications of increases in PO misuse in the general population, there is also evidence that such may be increasingly common in specific sub-populations. For example, recent youth or student drug use surveys in the U.S. suggested that POs have been among the most frequently misused drugs among older secondary students, second in prevalence only to marijuana when compared to illicit drug use (Compton & Volkow, 2006). In the Monitoring the Future (MTF) survey, the annual prevalence of narcotics use (other than heroin) more than doubled among 12th graders between 1992 and 2000. The annual prevalence of OxyContin (Oxycodone) abuse was 5% among students surveyed, reflecting a significant prevalence increase between 2002 and 2004 alone (Johnston, O'Mallley, Bachman, & Schulenburg, 2002). A longitudinal survey of illicit and non-medical prescription drug use in a nationally representative sample of college students in the U.S. saw the prevalence of PO misuse (in the last 12 months) more than double between 1993 (3.1%) and 2001 (7.3%), with prevalence and increase levels for POs higher than any other prescription or illicit drug (except for marijuana) in 2003 (McCabe, West, & Wechsler, 2007). These and similar other data corroborate Hurwitz's (2005, p. 153) analysis that "illicit pain reliever use ... disproportionately effects the young" (e.g., 12-25 years). Sung, Richter, Vanghan, Johnson, & Thom (2005), on the basis of longitudinal NSDUH prevalence data on adolescents (12-17 years) in the U.S., concluded PO misuse to be a new drug use epidemic beginning in the mid 1990s (2005, p. 44). Specifically, in 2002, 7.6% of adolescents reported PO misuse for the past year. Reported lifetime prevalence increased from 2.7% in 1995 to 11.2% in 2002; the number of annual incident users increased from 270,000 (1995) to 1,124,000 (2001). Furthermore, Sung et al. (2005) refute popular suggestions that young PO users tend to be white-collar, middle-class; rather they are mainly lower-income youth at high-risk for other illicit and/or poly-drug use (2005, p. 50).
Several North American studies show that PO misuse may have substantially increased in street drug user populations. Recent studies assessing populations at entry to methadone maintenance treatment (MMT) in both Canada and the U.S. found that substantial majorities were active misusers of POs, compared to minorities of heroin users (Rosenblum, Parrini, Schnoll, Fong, Maxwell, Cleland, et al., 2007; Brands, Blake, Sproule, Gourlay, & Busto, 2004). PO misuse furthermore has been reported by substantial proportions of street drug user populations outside of the treatment system (Fischer, Rehm, Patra, & Firestone, 2006b; Davis & Johnson, 2008). Specifically, in a longitudinal multi-site cohort of regular illicit opioid and other drug users (N=585) in Canadian cities in 2005, PO drugs (primarily hydromorphone, codeine, or oxycodone) were more prevalent than heroin (for the last 30 days) in five of the seven city samples (Fischer, Firestone, Cruz, & Rehm, 2006a). Moreover, longitudinal analyses showed that the prevalence of heroin use had significantly decreased among untreated participants since baseline (2001 onward) in all study sites, suggesting a recent shift from heroin to PO use in the study sample. Notably, heroin use was limited to large urban centers (e.g., Vancouver and Montreal), whereas PO use was concentrated in smaller cities. Similarly, anecdotal and media reports on PO misuse--primarily focusing on OxyContin (Oxycodone), dubbed Hillbilly Heroin--have emerged in both Canada and the U.S. in the past few years, notably in smaller urban or rural areas without viable heroin markets (Tough. 2001; The Fifth Estate, 2003). A recent study from rural Appalachian Kentucky (Havens, Walker, & Leukefeld, 2007) describing a cohort (N=184) of rural PO (mainly Oxycodone, hydrocodone and non-prescribed methadone) misusers showed that only 10% of the sample had ever used (injected) heroin (Havens et al., 2007). Cicero and colleagues (2005)--which found Oxycodone to be the most prevalently misused PO in their U.S. study--expected such use to be highest in areas with high heroin use, yet concluded this prediction to be "entirely wrong". Rather, "[OxyContin] abuse was concentrated in small- to medium-sized urban, suburban and rural areas" (2005 p. 670).
General use and availability of POs
Essential context for the phenomenon of PO misuse concerns the general (medical) availability and use of PO substances as...
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