A Practice Review of Medical Cannabis for Workplace Injuries

Over recent years there has been substantial research as well as clinical, policy, and consumer interest in medicinal cannabinoids as treatments for workplace injuries. While they are most often used for the treatment of pain and mental health conditions, large systematic reviews for these conditions suggest limited benefits contrasted with commonly experienced adverse effects and a need for further research to inform clinical practice.

WorkSafe Australia engaged us to update the findings of a previous review commissioned by WorkSafe Victoria. This review from the ISCRR (the Institute for Safety, Compensation and Recovery Research) related to the use of medical cannabinoids in the treatment of chronic pain, opioid-sparing effects, mental health disorders, nausea, and sleep disorders.

Despite considerable consumer and clinical interest, there have been few high-quality trials demonstrating efficacy or safety, and often conflicting recommendations made in different reviews. Several well-respected Australian and international professional organisations (e.g., the Australia and New Zealand Faculty of Pain Medicine and International Association for the Study of Pain (IASP)) currently recommend the use of medical cannabis products should be limited to the context of clinical trials. However, given the considerable volume of ongoing research exploring the potential for medical cannabinoids, recommendations and policies may change as new evidence emerges. For example, a recent review of the opioid-sparing effect of cannabinoids identified 15 ongoing clinical trials in December 2020.

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What did we do?

Our researchers conducted a rapid evidence and practice review including desktop and systematic reviews and meta-analyses of primary studies, as well as a series of expert interviews across Australia, Canada and the US via Zoom.

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What did we find?

Our rapid evidence and practice into the use of cannabinoids for the treatment of a range of medical conditions produced the following results:

For chronic pain, primary studies didn’t make strong recommendations in support of the use of medicinal cannabis for pain. In addition, no evidence that non-inhaled forms of cannabinoids were cost-effective was found.
For sleep disorders, there was weak evidence that supported the use of cannabinoids.

For mental health disorders, there was insufficient evidence to recommend their use.
For opioid-sparing effects, no evidence to reduce opioid doses was found.
For inflammatory bowel disease: insufficient evidence was found.
For adverse effects: inhaled cannabis was associated with specific adverse events like reduced lung capacity. In addition, there is potentially higher vulnerability to substance abuse disorders when using cannabinoids to treat bipolar, depressive, or anxiety disorders. It was also suggested alternative approaches be considered before considering cannabinoids due to adverse effects.

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What’s next?

There is currently heightened interest to change the regulation of cannabis products from the current Special Access Scheme to less regulation, with conflicting recommendations made in different reviews.

Our findings are consistent with the two previous ISCRR reviews; generally, the evidence for positive indications for the use of medical cannabis in the workplace is inconclusive, with little or no effect.

While several studies highlighted the safety concerns related to using cannabinoids for workplace injuries, across all conditions with the update review, there is insufficient evidence to support a shift in WorkSafe Victoria’s medical cannabis policy.