Systematic review of cannabis use and risk of occupational injury (2020)

Aim: A range of nations, including countries of the European Union, Australia, and the Americas have recently implemented or proposed reforms to how they control cannabis use, thereby departing from traditional approaches of criminal prohibition that have dominated throughout most of the twentieth century. Given these policy developments and the widespread global use of cannabis, it is critically important to understand the possible risks associated with cannabis use in relation to major societal harms.
Methods: This systematic review investigates the potential link between cannabis use and occupational injury. Consequently, it appraises all available current literature from five databases, following Cochrane and PRISMA guidelines.
Results: Seven of the 16 reviewed studies show evidence supporting a positive association between cannabis use and occupational injury. One study shows evidence supporting a negative association and the remaining eight studies show no evidence of a significant relation. None of the studies assessed cannabis-related impairment. Only three of the reviewed studies show clear evidence that cannabis use preceded the occupational-injury event.
Conclusion: The current body of evidence does not provide sufficient evidence to support the position that cannabis users are at increased risk of occupational injury. Further, the study quality assessment suggests significant biases in the extant literature are present due to potential confounding variables, selection of participants, and measurement of exposures and outcomes. Future high-quality evidence will be needed to elucidate the relation between cannabis use and occupational injury.