Opioid and healthcare service use in medical cannabis patients with chronic pain: a prospective study.

MC may be related to a significant yet small reduction in opioid prescription medication. Further prospective studies with representative samples are warranted to confirm the potential small opioid-sparing effects of MC treatment, its clinical importance, if any, and potential lack of association with other healthcare-related services and medication use. Due to methodological limitations of the data used in this study, results may be regarded as preliminary and causal inferences cannot be made.