Do consumers substitute opium for hashish? An economic analysis of simultaneous cannabinoid and opiate consumption in a legal regime

What does the ecological and epidemiological evidence indicate about the potential for cannabinoids to reduce opioid use and harms? A comprehensive review

Pre-clinical research supports that cannabinoids reduce opioid dose requirements, but few studies have tested this in humans. This review evaluates ecological and epidemiological studies that have been cited as evidence that medical cannabis use may reduce opioid use and opioid-related harms. Medline and Embase were searched for relevant articles. Data were extracted on study setting, analyses approach, covariates, and outcomes. Eleven ecological and 14 epidemiological studies were found. In ecological studies, states that allow medical cannabis laws have reported a slower rate of increase in opioid overdose deaths compared with states without such laws. These differences have increased over time and persisted after controlling for state sociodemographic characteristics and use of prescription monitoring programmes. Few studies have controlled for other potential confounders such as opioid dependence treatment and imprisonment rates. Some epidemiological studies provide evidence that cannabis availability may reduce opioid use, but are limited by selection bias, cross-sectional designs, and self-reported assessments of the opioid-sparing effects of cannabis. Some epidemiological and ecological studies suggest that cannabis may reduce opioid use and harms, although important methodological weaknesses were identified. Well-designed clinical studies may provide more conclusive evidence on whether cannabinoids can reduce opioid use and related harm.

Preclinical Studies of Cannabinoid Reward, Treatments for Cannabis Use Disorder, and Addiction-Related Effects of Cannabinoid Exposure

Cannabis use has become increasingly accepted socially and legally, for both recreational and medicinal purposes. Without reliable information about the effects of cannabis, people cannot make informed decisions regarding its use. Like alcohol and tobacco, cannabis can have serious adverse effects on health, and some people have difficulty discontinuing their use of the drug. Many cannabis users progress to using and becoming addicted to other drugs, but the reasons for this progression are unclear. The natural cannabinoid system of the brain is complex and involved in many functions, including brain development, reward, emotion, and cognition. Animal research provides an objective and controlled means of obtaining information about: (1) how cannabis affects the brain and behavior, (2) whether medications can be developed to treat cannabis use disorder, and (3) whether cannabis might produce lasting changes in the brain that increase the likelihood of becoming addicted to other drugs. This review explains the tactics used to address these issues, evaluates the progress that has been made, and offers some directions for future research.