Abstract
Introduction The United States is in the midst of an opioid overdose
epidemic. Emerging evidence suggests that medical cannabis (MC) may reduce use
of opioids for pain in some individuals, with potential impacts on
opioid-related overdose. However, there may be other important differences
between states that did, and did not, adopt MC.
Methods This study evaluated differences following legal MC sales on US
opioid-related overdose deaths, corrected for population, from 1999 to 2017
using an interrupted time series. Comparisons by MC status were also made for
Medicaid expansion and the Centers for Disease Control death certificate
reporting quality (0: <good, 1: good, 2: excellent).
Results Overdose deaths were significantly higher in MC states from
2012–2017. Overdose death slopes over time increased in states with
(pre=1.46±0.46, post=2.90±0.58, p<0.05)
and without (pre =0.20±.10, post=1.04±0.22,
p<0.005) MC. Post-legalization slopes were significantly higher in MC
states (p<0.01). Two states without (11.1%) as compared to 11
states with (91.7%) MC expanded Medicaid by 2014
(χ2[1]=19.03, p<0.0005). MC states
(1.50±0.23) had higher death certificate reporting quality relative to
states without MC (0.78±0.22, p<0.05).
Discussion MC states had higher rates of opioid overdoses. Although there
was no decrease in association with MC introduction, these results were
confounded by states without MC having lower overdose reporting quality.
Medicaid expansion was also more common in states with MC. Finally, the potency
of fentanyl analogues may have obscured any protective effects of MC against
illicit opioid harms.
