Co-Occurrence of Alcohol, Drug Use, DSM-5 Alcohol Use Disorder, and Symptoms of Drug Use Disorder on Both Sides of the U.S.-Mexico Border

Background: The U.S.-Mexico border displays elevated rates of hazardous alcohol and drug use. Whether the co-occurrence of alcohol and drug use and disorders is also high in the border area is unknown. Methods: Data are from the U.S.-Mexico Study on Alcohol and Related Conditions, a cross-sectional survey of randomly selected respondents interviewed from 2011 to 2013. Participants included 1,690 Mexican Americans from Texas (572 in an off-border city and 1,118 from 3 border cities) and 1,293 Mexicans from Nuevo Leon and Tamaulipas (415 in an off-border city and 878 from 3 Mexican cities bordering Texas) who reported drinking in the last 12 months. Participants were interviewed regarding the prevalence of and risk factors for: (i) co-occurring hazardous alcohol use (5+/4+ at least monthly) and drug use (medical and illicit) and (ii) co-occurring presence of a DSM-5 alcohol use disorder (AUD) and 2 symptoms (hazardous use and quit/control) of drug use disorder (DUD symptoms). Results: Co-occurring hazardous alcohol and drug use was more common in the U.S. border cities (14.7%) than off-border (7.2%), but similar for Mexican border (1.2%) and off-border (1.4%) cities. Co-occurrence of AUD and DUD symptoms was likewise more common at the U.S. border (6.8%) than off-border (3.3%), as well as at the Mexican border (1.3%), compared to off-border (0.6%), but not statistically significant for Mexico. In models adjusting for demographics, mobility factors and exposure to the U.S. culture, border residence in both countries related to a nearly twofold increase in prevalence ratios (PRs) of co-occurring AUD and DUD symptoms (PR = 1.97, 95% CI = 1.36 to 2.85). Conclusions: Increased rates of co-occurring AUDs and DUDs suggest an added negative impact on already difficult conditions of the border population.