Summary by John Searles, VDHl,
(Olfson et al., 2017, American Journal of Psychiatry, epub before print, September 26, 2017)
This article discusses previous research that appeared to demonstrate a relationship between medical marijuana availability and reduction in overdose death rates from prescription opioid analgesics. These three articles have been prominent in the push toward legalization. However, these authors (and others) point out that it is not possible to determine individual level of risk from these types of studies. The report describes analyses of Wave 1 and Wave 2 (three years apart) data from the National Epidemiolocal Survey of Alcohol and Related Disorders (NESARC).
Results (Background): Wave 1 individuals who reported any past-year cannabis use were more likely to be younger, male, have a past-year opioid use disorder, cannabis use disorder, other substance use disorder or any past year mood or anxiety order.
Results (Prospective Associations): “After adjustment for the background demographic and clinical characteristics, a strong association persisted between wave 1 cannabis use and wave 2 prevalent nonmedical opioid use. Among individuals without nonmedical opioid use during the 12 months before the wave 1 interview, there was a significant association between cannabis use at wave 1 and incident nonmedical opioid use during the follow-up period.” (p.3) Further “cannabis use at wave 1 was associated with a significant increase on the odds of prevalent and incident [initiators] prescription opioid use disorder during the follow-up period.” (p.3) Thus, any cannabis use at wave 1 was significantly associated with an increase in prevalence of nonmedical opioid use as well as a significant increase in the number of new cases of nonmedical opioid use in wave two. This effect was dose dependent
“In a nationally representative sample of adults evaluated at waves 3 years apart, cannabis use was strongly associated with subsequent onset of nonmedical prescription opioid use and opioid use disorder. These results remained robust after controlling for the potentially confounding effects of several demographic and clinical covariates that were strongly associated with cannabis use. The association of cannabis use with the development of nonmedical opioid use was evident among adults without cannabis use disorders and among adults with moderate or more severe pain. Among adults with nonmedical prescription opioid use, cannabis use was associated with an increase in the level of nonmedical prescription opioid use at follow-up.” (pp 3-4)
“Ecological studies reporting fewer opioid-related deaths and decreased opioid prescribing following passage of medical marijuana laws [Bradford & Bradford, 2016] have been interpreted in the media and scientific literature as supporting cannabis as a means of reducing opioid use disorder. Yet drawing inferences about the behavior of individuals from aggregated data can be misleading. It is possible, for example, that passage of medical marijuana laws increased local clinical awareness of opioid misuse, leading to earlier detection of high-risk patients or more cautious opioid prescribing practices. At the individual level, cannabis use appears to substantially increase the risk of nonmedical opioid use. Moreover, the general association between cannabis use and subsequent use of illicit drugs is not explained by the legal status of cannabis. An association of early cannabis use with increased subsequent risk of other drug abuse has been reported in prospective co-twin studies in Australia, which has restrictive cannabis laws, and in the Netherlands, where cannabis is readily available.” (pp 5-6)
“If cannabis use tends to increase opioid use, it is possible that the recent increase in cannabis use may have worsened the opioid crisis.” (p5)
|Non-Medical Use of Prescription Opioids Past Year||Cannabis Use Past 12 Months (%)||No Cannabis Use (%)|
|Very Frequent Use||3.6||0.2|
|Opioid Use Disorder||4.1||0.2|
|Cannabis Use Disorder||36.2||0|
 Bachhuber et al.(2014). Medical Cannabis Laws and Opioid Analgesic Overdose Mortality in the United States. JAMA Internal Medicine, 174, 1668-1673.
Powell et al. (2015). Do medical marijuana laws reduce addictions and deaths related to pain killers? NBER Working Paper No. 21345. Cambridge, MA: National Bureau of Economic Research.
Bradford & Bradford (2016). Medical Marijuana Laws Reduce Prescription Medication Use in Medicare Part D. Health Affairs, 35, 1230-1236.
 Finney et al. (2015). What Ecological analyses Cannot Tell Us About Medical Marijuana Legalization and Opioid Pain Medication Mortality. JAMA Internal Medicine, 175, 655-656.
 NESARC “is a nationally representative sample of the noninstitutionalized adult U.S. population conducted by the U.S. Census Bureau under the direction of the National Institute on Alcoholism and Alcohol Abuse.” (p.2)
 Adjusted for age, sex, race/ethnicity, other substance use disorders, any mood or anxiety disorder, and family history of drug use disorder, alcohol use disorder, depression, and antisocial/personality disorder at wave 1.
 Zhang (2016). Patients Are Ditching Opioid Pills for Weed: Can Marijuana Help Solve the Opioid Epidemic. Atlantic, February 2.
 Miller, (2016). Could Pot Help Solve the US Opioid Epidemic? Science, November 3.
 Hasin et al. (2015). Prevalence of Marijuana Use Disorders in the United States between 2001-2002 and 2012-2013. JAMA Psychiatry, 72, 1235-1242.
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