Driving under the influence of cannabis (DUIC) is framed as a major risk associated with legalizing cannabis. Studies on cannabis and driving suggest that lighting up before getting behind the wheel increases crash risk between 25-40%. This is equal to the effect of having a single drink one hour before driving.

The development of legal cannabis is associated with lower teen use and higher adult use. But many scientists, hesitant to give up a lifetime of prohibition, spin their data to emphasize danger. One study from 2017 had shown that attending college is a risk factor for trying cannabis, and suggested that political acceptance of cannabis is promoting use among college students. But this interpretation was taken to task by a scientist at Washington University in St. Louis.

There has been a spate of recent articles on exercise and cannabis. Part of the runner’s high is attributable to endocannabinoid release. In Colorado, cannabis users are more physically active, on average. And in a recent review, Chinese scientists at Shenzhen University describe how the endocannabinoid system may mediate the numerous cognitive effects of exercise.

Opioids leave much to be desired in medical treatment. They are highly addictive, very lethal, and not all that effective for treating chronic pain. Cannabis, particularly THC, is promising for its opiate-sparing properties: preclinical work indicates that cannabis synergizes with the painkilling effects of opioids and reduces the development of tolerance (perhaps because of this synergy) but does not increase opioid-induced respiratory depression which leads to death. Moreover, states that legalize cannabis see a decrease in opioid prescriptions.