Prescription anxiety medications (including sedatives and tranquilizers) have great clinical efficacy (
1,
2) and are widely prescribed (
3) in the United States. However, in recent years, the nonmedical use of prescription anxiety medications has increased (
4–6). Nonmedical use includes use without a doctor's prescription, or use in greater amounts, more frequently, or longer than prescribed or for a reason other than that recommended by a doctor (
4,
5). Nonmedical use of prescription anxiety medication can be dangerous and even fatal (
2,
7,
8), as evidenced by an estimated 233,875 nonmedical use-related emergency department visits in 2006 (
8). Prescription anxiety medications exhibit stronger reinforcing properties than other prescription psychiatric drugs, and these properties are amplified with nonmedical use (
1,
2,
7). Consequently, among non-medical users of prescription anxiety medications, estimates of drug use disorders secondary to such use are high (
4,
5,
9). Thus, the nonmedical use of these agents represents a growing and important public health problem. To develop effective prevention and treatment interventions, an improved understanding of nonmedical use of prescription anxiety medication is necessary, including risk factors.
Previous studies indicate that individuals with anxiety disorders have an elevated risk of nonmedical use of prescription anxiety medications (
4). However, whether the risk of nonmedical use is increased by receiving a prescription for anxiety medication is unknown. In addition, little is known about nonmedical use of prescription anxiety medication among individuals who have a prescription, since previous epidemiological studies asked only about nonmedical use “without a prescription” (
10,
11) or did not distinguish between nonmedical use with and without a prescription (
5). School-based and Internet surveys suggest that many individuals with a prescription for psychiatric medication engage in nonmedical use of their own prescriptions (
12,
13; unpublished data, available on request from the first author). Thus, while these medications can be obtained and used nonmedically through street sales and prescription drug sharing, individuals with a prescription for anxiety medication may also have an elevated risk of developing drug use disorders secondary to use of prescription anxiety medication. Consequently, there is a need for epidemiological research to obtain estimates and correlates of nonmedical prescription anxiety medication use, abuse, and dependence among individuals with a prescription for such medications.
We investigated these issues using data from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), sponsored by the National Institute on Alcohol Abuse and Alcoholism (NIAAA). The NESARC is unique in its sample size, representativeness, and comprehensiveness, allowing for generalizable estimates. In this study, we considered two general questions: 1) Is the prevalence of nonmedical prescription anxiety medication use and associated drug use disorders (i.e., abuse and dependence) higher among individuals with a prescription for an anxiety medication than it is among individuals without a prescription? 2) What behavioral, psychiatric, and family history characteristics are associated with nonmedical use of anxiety medications among individuals with a prescription?
Discussion
To our knowledge, this is the first study to examine the prevalence of nonmedical prescription drug use among individuals with and without a prescription, using a nationally representative sample. We found that 16.0% of respondents with a prescription for anxiety medication reported nonmedical use, compared with 6.3% among individuals without a prescription. Likewise, 6.0% of individuals with a prescription reported a drug use disorder secondary to prescription anxiety medication, compared with only 1.9% among individuals without a prescription. Our findings support the hypothesis that individuals with a prescription for anxiety medication are at significantly elevated risk of nonmedical use (
1,
4,
5). Notably, we found that this phenomenon cannot be fully accounted for by anxiety disorder diagnoses, anxiety disorder severity, or co-occurring drug use.
Our findings are consistent with non-population-based surveys that reveal high rates of nonmedical prescription medication use among individuals with a prescription (
12,
13; unpublished data, available on request from the first author). No estimates of prescription drug use disorders due to nonmedical use among individuals with a prescription have been published previously. However, around 70% of respondents with a prescription in our sample met criteria for at least one lifetime anxiety disorder diagnosis, and previous population-based (
4,
5) and clinical (
32) studies have indicated an association between anxiety disorders and drug use disorders secondary to nonmedical use of prescription drugs. Since anxiety medications have significant therapeutic value, research establishing the causes of nonmedical use, abuse, and dependence among those with a prescription is needed.
Among individuals with a prescription, behavioral characteristics associated with nonmedical use included illicit drug use, driving while intoxicated, and substance-related criminal activity. Our findings correspond with characteristics associated with college nonmedical prescription anxiety medication users (
10). These behavioral characteristics are components of some psychiatric disorders, particularly substance use disorders, which may explain why most substance-related behavioral characteristics lost significance when the analyses controlled for psychiatric disorders. It is especially noteworthy that illicit drug use and selling drugs or stolen property remained significant predictors of nonmedical use even when the analyses controlled for psychiatric characteristics.
Among individuals with a prescription, all psychiatric disorders were significant predictors of nonmedical prescription anxiety medication use in the first set of models. This finding is consistent with previous reports of a high prevalence of psychiatric disorders among nonmedical prescription anxiety medication users in the general population (
4,
5,
9). However, adjusting for all sociodemographic, behavioral, and psychiatric characteristics, significant associations were observed only for any drug use disorder and any personality disorder. This suggests that drug use and personality disorders exert a unique effect on nonmedical prescription anxiety medication use, while the effect of other psychiatric characteristics may be due to shared underlying factors. Our results should not be interpreted as indicating a need to withhold potentially important medications from patients. Rather, the findings suggest the need for greater attention to the recognition and management of comorbid psychiatric conditions, particularly personality and drug use disorders, by health care workers involved in pharmacological treatment of anxiety disorders, such as by screening for other substance use disorders before prescribing anxiety medication and monitoring for nonmedical use of prescribed anxiety medication throughout the course of treatment. Prescribers may also consider including an adjunct psychotherapeutic component to their anxiety disorder treatment to identify, treat, and prevent the development of problems with nonmedical use.
Our study had several limitations. First, all survey questions may have been subject to recall, self-report, and social desirability bias. Second, since only information on lifetime prescription was available, the prescription anxiety medication used nonmedically may not have been the anxiety medication for which respondents had received a prescription; future studies should include questions specific enough to ascertain this information. Third, to maximize statistical power, our definition of nonmedical use was broad, including one-time nonmedical use. However, excluding respondents who engaged in nonmedical anxiety medication use only once within any single year did not change the significance or strength of the association between having a prescription and lifetime nonmedical use. This indicates that our result did not derive from these respondents only. Additionally, the survey questions on nonmedical use did not cover dangerous nonmedical use behaviors (e.g., intranasal administration and coadministration with other psychoactive substances) while using prescription anxiety medication for the appropriate medical reason. Also, anxiety disorders are occasionally treated with medications other than antianxiety drugs (
33), which may have introduced error into our measure of prescription anxiety medication use, although other medications are prescribed on such a limited basis that this is unlikely to change the results. Additionally, some anti-anxiety medications may have been prescribed for major depression (
34), potentially biasing the associations observed in this study toward the null, yielding conservative results. Furthermore, while the gateway questions that screened respondents into the treatment questions were broad, the prescription questions were not asked of all respondents, potentially introducing misclassification bias. However, this possibility is reduced because prescription of medication for any anxiety disorder was assessed in 11 different questions in the wave 1 and 2 interviews, and two-thirds of the sample (67.1%) were asked at least one of these questions.
The study also has several notable strengths. It is the first attempt to consider the nonmedical use of prescription anxiety medication among individuals with a prescription. The sample was large and produced nationally representative findings. Data from two time points were included. And, finally, we were able to examine an important question for which data were previously unavailable.
Research on nonmedical prescription anxiety medication use among psychiatric patients does not detract from the great clinical utility of prescription anxiety medication (
1,
2). Development of interventions targeting nonmedical use among patients with a prescription must take care not to reduce prescription of these drugs for patients who need and will benefit from them. Appropriate development of interventions will require an understanding of the characteristics predisposing to nonmedical use among patients with a prescription. The information we provide here on sociodemographic, behavioral, and psychiatric characteristics associated with nonmedical use of anxiety medication among individuals with a prescription can be used in the design of such interventions.