Exclusion of Benzodiazepines

Around the globe, there is considerable illicit (i.e. extra-medical) use of pharmaceutical drugs such as benzodiazepines. In recognition of this, we have attempted to find the existing epidemiological data on the prevalence, incidence, duration and related mortality of illicit benzodiazepine use and dependence. We also attempted to locate existing epidemiological data on the risks for adverse consequences of illicit benzodiazepine use.

The research teams working on the collection and analysis of data on illicit benzodiazepine use, dependence, and for benzodiazepine use as a risk factor for other adverse consequences. “Gold standard” searches were conducted of Embase, PsycInfo and Medline to find data in the peer reviewed literature¹ and in the “grey” literature². Despite using these approaches, the following facts regarding both the nature of existing evidence and of the epidemiology of illicit benzodiazepine dependence are evident:

1. There is an absence of epidemiological data specific to illicit benzodiazepine use/dependence in the general population for many countries worldwide;
2. The studies that do exist find an extremely high rate of comorbid illicit drug use problems, particularly opioids (e.g.^3,4). In the GBD exercise, we propose that associated burden would be attributed to opioids;
3. Although there is evidence suggesting increased mortality in regular users over 60 years of age, compared to younger people, it is not clear whether this use is in accordance with a medical professional’s advice, and so cannot necessarily be attributed to “illicit” use¹;
4. There is good evidence from a prospective cohort study of injecting drug users of increased mortality associated with benzodiazepine use among illicit drug users, typically opioid users¹. However, in the current GBD exercise, overdoses where opioids are involved as well as other drugs will be attributed primarily to opioid use; and
5. There is no strong positive association with driver culpability in fatal road accidents¹

For these reasons, it is proposed that there is currently insufficient data to allow an accurate estimate of the burden attributable to illicit benzodiazepine dependence worldwide. We propose excluding benzodiazepines as a separate drug class for the illicit drug burden estimation process. The failure to include these drugs does not imply that the illicit use of these drugs is without risk to users.

References

1. Charlson, F., Degenhardt, L., McLaren, J., Hall, W., & Lynskey, M. (2008). Benzodiazepinerelated mortality. Global Burden of Disease Mental Disorders and Illicit Drug Use Expert group, Illicit drugs discussion paper No. 1. National Drug and Alcohol Research Centre, University of NSW: Sydney.
2. Calabria, B., Phillips, B., Singleton, J., Mathers, B., Congreve, E., Degenhardt, D., & McLaren, J. (2008). Searching the grey literature to access information on drug and alcohol research. NDARC Technical Report No. 293. Sydney: National Drug and Alcohol Research Centre, University of New South Wales. Full text PDF
3. Brady KT, Johnston AL, Cunningham M, Malcolm R. Profiles of hospitalized benzodiazepine abusers. Journal of Psychoactive Drugs 1991;23(1):71-72.
4. Longo LP, Johnson B. Addiction: Part I. Benzodiazepines - side effects, abuse risk and alternatives. American Family Physician 2000;61(7):2121-2128.