Sex differences in cannabis- and alcohol-related motor vehicle collisions in three U.S. states with legalized cannabis: A multicenter observational study

OBJECTIVES: As recreational cannabis legalization expands in the United States, concerns about cannabis-impaired driving and traffic injury risk have increased. Although cannabis impairs driving performance, less is known about how sex-specific behavioral and psychosocial contexts shape pathways to motor vehicle collisions (MVCs), particularly in legalized settings. We examined sex differences in cannabis and alcohol use, driving behaviors, mental health context, and crash-related outcomes among injured drivers. METHODS: We conducted a secondary analysis of a multicenter cross-sectional study of 813 adults presenting to emergency departments in Denver, Portland, and Sacramento within 8 h of an MVC. Recent cannabis and alcohol use were identified using self-report and biological testing. Sex-specific differences in substance use, driving behaviors, mental health indicators, and clinical outcomes were evaluated using descriptive statistics. RESULTS: = 0.005). Male drivers more frequently engaged in high-risk driving behaviors, including higher reported speeds, use of open vehicles, and vehicle rollovers, and were more often admitted to the hospital (58% vs. 43%). Female drivers more commonly reported cannabis use for anxiety and a higher burden of posttraumatic stress symptoms (24% vs. 17%). Injury severity scores were similar between sexes. CONCLUSIONS: Similar prevalence of cannabis use among injured drivers concealed distinct sex-specific pathways to MVC risk. Among men, alcohol co-use and high-risk driving behaviors represented established mechanisms of crash severity and health-care utilization. Among women, cannabis use more often occurred within a mental health context, suggesting different pathways linking substance use to traffic injury risk. Traffic injury prevention strategies in legalized cannabis environments should incorporate sex- and gender-responsive approaches, including targeted interventions addressing polysubstance use and hazardous driving behaviors, and integration of mental health considerations into impaired-driving prevention.