Among this representative national sample of adolescents aged 12–17 years, about 7% reported PPR use without a prescription in the previous 12 months, and approximately 1% met criteria for past-year PPR abuse or dependence. Among the subset of past-year non-prescribed users, we found that 16% of users met criteria for abuse (7%) or dependence (9%), and an additional 20% exhibited subthreshold dependence. Individuals in the latter group have typically not been recognized (“diagnostic orphans”). Thus, if we had relied exclusively on the formal DSM-IV classification, we would have overlooked one-fifth of past-year non-prescribed PPR users who reported symptoms of dependence.
The most salient finding of this study is the high prevalence of clinical features of abuse or dependence among adolescent users of non-prescribed PPRs: more than one in three users reported one or more DSM-IV criterion symptoms, and close to one in six met criteria for abuse or dependence. This observation is in agreement with the pattern of non-prescribed PPR use reported by all users in this sample: they reported, on average, using PPRs for 38 days in the past year and using two categories of PPRs. This finding is also is consistent with recent studies that have revealed substantially increased rates of PPR-related admissions to emergency departments and publicly funded substance abuse treatment facilities.6–8,24
However, the lack of research on PPR use disorders among adolescents has constrained our ability to compare our findings with those of others. We have found one study that reported the prevalence of PPR abuse and dependence among youth. In their sample of youth aged 14–24 in Germany,25
investigators reported that about 8% of lifetime non-prescribed PPR users (N = 114) met criteria for DSM-IV PPR abuse (4.3%) or dependence (3.5%) and an additional 21% met criteria for subthreshold dependence. Although past-year PPR abuse and dependence was not reported by Perkonigg et al.,25
our findings clearly show that use of non-prescribed PPRs among domicile American adolescents is noteworthy and deserves further research and attention.
Results from this study also suggest that the DSM-IV classification may be insufficient to capture the heterogeneity of symptoms presented by adolescent PPR users. Although the DSM-IV,14
defines a hierarchical distinction between abuse and dependence and implies that abuse occurs before dependence, we found a much higher prevalence of dependence than abuse symptoms. All adolescents with subthreshold dependence (20% of non-prescribed users), as well as 42% of those with a dependence diagnosis (3.8% of non-prescribed users), reported no abuse symptom, as compared to 12% of non-prescribed users who reported at least one abuse symptom (i.e., 6.7% with an abuse diagnosis and 5.3% with a dependence diagnosis plus concomitant abuse symptoms). Considering the young age of this sample, our findings support the conclusion that dependence can occur in the absence of abuse, and that an exclusive reliance on the presence of abuse symptoms as a screener to identify cases of dependence is likely to miss cases where dependent individuals report no abuse symptoms.26
Consistent with the study of dependence symptoms from non-prescribed PPR use,27
we found that “tolerance” and “salience” were the most common symptoms experienced by users. Our results revealed further that both symptoms were endorsed by the great majority of the dependence group, and that “role interference” and “hazardous use” were cited as the most frequently exhibited symptoms of abuse. The latter two abuse symptoms were each reported by more than one-third of the dependence group and by more than one-half of the abuse group. Overall, adolescents classified as having dependence suffered the most clinical features from PPR use, including symptoms of physiological dependence (tolerance and withdrawal), compulsive PPR use behaviors (spending a great deal of using PPRs, giving up important activities, and continued use despite having psychological or physical problems), as well as consequences from PPR use (role interference and use in hazardous conditions). This higher rate of symptoms in the dependence group is likely related to the greater numbers of days that these adolescents reported using PPRs, as well as additional types of PPRs used.
Results from this study further suggest that a subgroup of vulnerable adolescents with depression or alcohol problems are at risk for using non-prescribed PPRs regularly, and that the odds of escalating to a diagnosis are closely associated with additional days of PPR use. We found that having MDEs or AUDs each increased adolescents’ odds of being classified in all three diagnostic categories. Past-year ED treatment also increased odds of PPR abuse and subthreshold dependence, and was marginally associated with dependence (AOR = 1.5, p
=0.059). Because “relieving pain” is much more likely than “getting high” to be endorsed by adolescent users of non-prescribed PPRs as the primary reason for their use,11
it seems likely that PPRs are taken to reduce the discomfort associated with physical or mental health problems,28
and that the risk of developing abuse or dependence may be exacerbated by existing physical and mental health conditions.
Compared with PPR users who reported no DSM-IV symptoms, abusers were generally younger, likely to be non-students, had already received services for psychological problems, reported fair/poor health, and had a history of MDEs. Because the abuse group was unassociated with engagement in criminal activities and use of multiple drugs, it seems likely that they had suffered internalizing problems and might have used PPRs for self-medication to alleviate mental health-related conditions.28
Given the young age of this group, longitudinal studies are needed to determine whether the subset of young abusers progresses to dependence as suggested by the DSM-IV (i.e., abuse occurs before dependence).
In contrast, adolescents categorized as dependent, as compared to PPR users who reported no DSM-IV symptoms, were likely to report past-year MDEs, to sell illicit drugs, and to use multiple drugs in the past year, suggesting co-occurrences of internalizing and externalizing problems. In this group, PPR use may be a manifestation of self-medication for mental health problems,28
delinquency, and polydrug use.29
Further, dependence on PPRs among girls deserves attention. Girls are more likely than boys to report a history of both prescribed (37% vs. 23%) and non-prescribed (22% vs. 10%) PPR use.11
They also are more likely than boys to give or loan their PPRs to others (e.g., female friends),30
but appear less likely to use them for getting high.31
Given that prescribed PPR use is associated with non-prescribed use and that girls may take PPRs to alleviate menstrual cramps,11
girls’ risk for dependence may be related to their greater access to PPRs11
and to their need to self-medicate to reduce discomfort or psychological distress. Additionally, non-prescribed PPR users typically obtain their PPRs from peers.32
Affiliation with PPR-using friends may thus pose a risk for non-prescribed use.
Lastly, the subthreshold dependence group is also characterized by past-year ED treatment, AUDs, use of multiple drugs, and MDEs. This group differs from the dependence group in a lack of association with delinquency variables examined. However, this group appears to be represented by African Americans and Asians/Native Hawaiians. Given its high prevalence, an exclusive use of the DSM-IV to find cases in need of clinical attention or research will likely miss minority adolescents who perceived adverse effects from PPR use.
Taken together, adolescents in the dependence group use more PPRs and exhibit more DSM-IV symptoms than adolescents in the other groups. They also appear to be more likely than abusers to use multiple drugs, be involved in criminal activities, and experience MDEs recently. In this regard, dependence tends to be more severe than abuse as indicated by the DSM-IV.14
Additionally, subthreshold dependence (20%) is more common than the combined prevalence for abuse and dependence (16%), and this group resembles the dependence group in past-year MDEs, AUDs, and use of multiple drugs. Given the young age of this sample, prospective studies are needed to study the course and treatment needs of adolescents with subthreshold dependence. Adding a symptom count in addition to relying on the DSM’s formal classification criteria may help identify “diagnostic orphans of drug users” who otherwise could be missed by clinicians or researchers.
These findings should be interpreted within the context of the following limitations. First, due to the cross-sectional nature of the survey, no causal pathways among the variables examined can be inferred. Self-reports on which this study relies are influenced by various biases, including memory errors and under-reporting due to social desirability biases. In addition, a small (less than 2%) subgroup of adolescents, including incarcerated, institutionalized, and homeless adolescents, was not included in the NSDUH. These findings do not apply to them. Further, while the diagnoses of abuse and dependence were assessed by standardized questions administered by trained interviewers, they were not validated by clinicians.
Moreover, non-prescribed PPR use is defined broadly.10, 33
This definition may have led to the inclusion of users who had a legitimate medical condition but lacked a prescription for various reasons.10,33
The wording of the survey questions might have served to include PPR users who received medication from friends or family members to alleviate their health-related conditions.10, 33
Nevertheless, our findings are generally in agreement with research on students indicating an association of substance use with non-prescribed PPR use.11
Last, although the NSDUH explicitly listed more categories of PPRs used than the other population-based surveys,4,26
it should be noted that the 21 categories of PPRs specified in the survey are not entirely inclusive. There are a few PPRs that are not listed by the survey.
In conclusion, more than one-third of adolescent users of non-prescribed PPRs report DSM-IV symptoms of abuse or dependence. Unsupervised use of prescription PPRs places users at risk for adverse interactions with other central nervous system depressants, for overdose, and for addiction.9,34,35
Considering that family members and friends constitute sources of PPRs for adolescents,30
issues concerning the health risk of unsupervised use of prescription PPRs should be included in adolescent drug prevention education efforts among families and in the community.