The Mexican migration to the United States and substance use in northern Mexico

Aims   To examine the impact of migration to the United States on substance use and substance use disorders in three urban areas of northern Mexico.
Design   Cross-sectional survey of immigration-related experiences and life-time and past-year alcohol and drug use, in a representative sample of respondents aged 12–65 years.
Setting   Interviews were conducted in the cities of Tijuana, Ciudad Juarez and Monterrey during 2005. Respondents were classified into three groups: (i) 'return migrants', (ii) 'relatives of migrants' and (iii) 'others in the general population'.
Findings   A total of 1630 completed interviews were obtained for a response rate of 70.5%. 'Return migrants' were more likely to have used alcohol, marijuana or cocaine at least once in their life-time and in the last 12 months, more likely to develop a substance use disorder and more likely to have a 12-month substance use disorder compared with 'others in the general population'. Among 'return migrants', longer length of time in the United States and type of work performed as an immigrant were related to higher prevalence of substance use. Among 'relatives of migrants', migration experiences were not associated with increased prevalence of substance use compared with 'others in the general population'.
Conclusion   This study found a link between migration to the United States and the transformation of substance use norms and pathology in Mexico. Future research on pre-migration involvement in substance use and data on the timing of events among return migrants is needed. Public health measures are likely to require cross-border coordination of research and service development.