Cannabis Use Disorder Diagnoses in the VA Healthcare System Double Over the Past Seven Years
Cannabis has been the most widely used illicit substance in the United States for 30 consecutive years. Data from 2009 suggest that approximately 4.3 million Americans abused or were dependent on cannabis within the past year, the highest of any illicit substance. Further, more frequent use is related to an increased risk of dependence. Although rates of cannabis use and its disorders have been documented at the national level, there has been little study of the prevalence of diagnosed cannabis use disorder (CUD) among Veterans. This study examined current rates and trends of CUD diagnoses among Veterans who used the VA healthcare system during fiscal years 2002, 2008, and 2009. Using VA's National Patient Care Databases (NPCD — an administrative database), investigators categorized Veterans into three groups: 1) Veterans with a CUD, but no other illicit substance use disorder (SUD), 2) Veterans with an alcohol use disorder, but no illicit SUD, and (3) Veterans with either an amphetamine, barbiturate, cocaine, or opioid use disorder. These data include all VA inpatient, residential, and outpatient encounters and diagnoses recorded during the encounter.
- The prevalence of CUD diagnoses overall within VA has increased nearly 60% (from 0.66% to 1.05%) over the past 7 years, with the prevalence of CUD diagnoses among those without other illicit SUD having risen 115% (from 0.27% to 0.58%) during the same time period. Rates of other substance use disorder diagnoses within VA (i.e., alcohol-only and other-drug disorder) increased to a much smaller degree.
- Although rates of CUD diagnosis within VA have increased dramatically, they remain significantly lower than rates of CUD observed in the U.S. population.
- States with laws allowing for the legal use of cannabis for medicinal purposes had significantly higher rates of CUD diagnoses within VA in 2002, 2008, and 2009.
- Rates of psychiatric diagnoses, and PTSD specifically, were higher among patients with a CUD diagnosis but no other illicit SUD, as compared to other SUD groups.
- Rates of specialty SUD treatment utilization among those with a CUD diagnosis but no other illicit SUD have decreased within VA.
- It is possible that the present findings are due to improved detection of CUD in Veterans because of an increased attention to the identification of alcohol misuse and mental health disorders within the VA healthcare system.
- There were no uniform criteria for clinically assigning the diagnosis of a CUD, substance use disorder, or psychopathology in the NPCD, and data regarding history of cannabis use are not systematically collected within VA.
- Inherent differences exist between VA and U.S. data used for comparison. For example, there was a mismatch in the age ranges in VA (age 18 or older) and SAMHSA data (age 12 or older), which could have accounted for some of the observed differences.
This study was funded through VA/HSR&D's Quality Enhancement Research Initiative (QUERI; RRP 10-192). All authors are part of HSR&D's Center for Health Care Evaluation in Palo Alto, CA.
Bonn-Miller M, Harris A, and Trafton J. Prevalence of Cannabis Use Disorder Diagnoses among Veterans in 2002, 2008, and 2009. Psychological Services May 7, 2012;Epub ahead of print.