Legalising cannabis in the US has seen fatal road crashes increase by up to 22 per cent in those states, a study reveals. The team from the University of Illinois Chicago looked at seven states that had recreational cannabis dispensaries and found that four of them had seen huge increases in road deaths.
And on average fatal crashes had gone up by ten per cent. Researchers used death certificate data to compare mortality rates in states that legalised recreational cannabis dispensaries with states that only provided access to medical cannabis.
They collected data from death certificates from 2009-2019 on deaths in three areas that have previously been linked to cannabis use but are still poorly understood: motor vehicle accidents, suicide and opioid overdose. The states involved were Alaska, California, Colorado, Massachusetts, Nevada, Oregon and Washington.
The data revealed significant increases in crash fatalities in Colorado (16%), Oregon (22%), Alaska (20%) and California (14%). However for opioid overdose deaths, recreational markets were associated with an 11 per cent reduction in fatalities, on average.
Across all seven states, the reduction ranged from three per cent to 28 per cent. However they found no evidence that recreational markets impacted suicides, which is notable because cannabis use is associated with the development of depressive disorders and suicidality.
Dr Samantha Marinello, first author of the study published in the journal Social Science & Medicine said: "To see a 10 per cent increase in motor vehicle accident deaths associated with recreational markets is concerning.
"Previous studies have found cannabis impairs driving ability and that driving while high is fairly common among regular cannabis users."
For each cause of death, the researchers compared trends in deaths in states with legal markets with those in states that had comprehensive medical cannabis programs and similar trends in death rates prior to implementing markets.
Dr Marinello added: “We didn’t want to compare states with very different mortality trends or social ideology, so we looked at each state and outcome and identified comparison states with existing medical cannabis programs and with similar pre-trends to conduct our analysis.
“The results suggest that a potential unintended consequence of recreational markets is increased cannabis-intoxicated driving and crash deaths, and, hence, a potential need for policies focused on reducing driving under the influence of cannabis.”
Dr Marinello said the findings suggest that it may be beneficial for states with legal recreational cannabis to invest in policies and public health initiatives to mitigate this potential harm and build awareness of the dangers of driving under the influence.
She added that the reduction in opioid overdose fatalities is another potential area of impact that should be a factor in states considering legalisation.
She said: “This study provides evidence of both potential benefits and harms that policymakers should consider when legalising recreational cannabis markets."
