Daily cannabis use is associated with greater odds of retention in treatment among those addicted to opioids, according to a new study published in the journal Addiction, and epublished online by the National Institute of Health.
“Cannabis use is common among people on opioid agonist treatment (OAT), causing concern for some care providers”, states the study. “However, there is limited and conflicting evidence on the impact of cannabis use on OAT outcomes. Given the “critical role of retention in OAT in reducing opioid-related morbidity and mortality”, researchers “aimed to estimate the association of at least daily cannabis use on the likelihood of retention in treatment among people initiating OAT.” As a secondary aim researchers “tested the impacts of less frequent cannabis use.”
The study comprised a total of 820 people who use illicit drugs (PWUD), who initiated OAT between December 1996 and May 2016. . Participants were followed for a median of 81 month.
The primary outcome was retention in OAT, defined as remaining in OAT (methadone or buprenorphine/naloxone-based) for two consecutive 6-month follow-up periods, and the primary explanatory variable was cannabis use (at least daily versus less than daily) during the same 6-month period. “Confounders assessed included: socio-demographic characteristics, substance use patterns and social-structural exposures.”
In adjusted analysis, “at least daily cannabis use was positively associated with retention in OAT [adjusted odds ratio (aOR) = 1.21, 95% confidence interval (CI) = 1.04-1.41]. Our secondary analysis showed that compared with non-cannabis users, at least daily users had increased odds of retention in OAT (aOR = 1.20, 95% CI = 1.02-1.43), but not less than daily users (aOR = 1.00, 95% CI = 0.87-1.14).”
Researchers conclude from this that “Among people who use illicit drugs initiating opioid agonist treatment in Vancouver, at least daily cannabis use was associated with approximately 21% greater odds of retention in treatment compared with less than daily consumption.”
More information on this study, conducted by researchers at the British Columbia Centre on Substance Use, the University of British Columbia, and Simon Fraser University – all in Canada – can be found by clicking here.