The frequency of non-aggressive symptoms in conduct disorder rises significantly across generations of Mexican-origin populations after they migrate to the United States, according to an international team of researchers.
Conduct disorder, as defined by the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) of the American Psychiatric Association, involves persistent symptoms including aggression or other violations of age-appropriate norms that cause significant clinical impairment.
Behaviors that characterize conduct disorder include bullying others, getting into fights, fighting with a weapon, cruelty to people or animals, stealing with confrontation, forced sex, property destruction, theft and rule breaking.
“Our study shows that there is a large difference in risk for conduct disorder between Mexicans living in Mexico and people of Mexican descent living in the United States,” said Sergio Aguilar-Gaxiola, a professor of clinical internal medicine at UC Davis.
“This increase in risk occurring across generations within a migrating population strongly points to the influence of early childhood environmental factors in the United States and the potential to intervene to reduce the prevalence of conduct disorder.”
For the study, UC Davis and RAND Corp. researchers evaluated the prevalence of conduct disorder associated with migration from Mexico to the United States. Conduct disorder symptoms were assessed across four groups of people of Mexican origin with the following levels of exposure to American culture: non-immigrant households in Mexico with no exposure to the United States, Mexicans from migrant households who lived in Mexico until age 15, children of Mexican migrants raised in the United States and Mexican-American children of U.S.-born parents.
The researchers gathered data by performing face-to-face interviews with nearly 1,800 adults aged 18 to 44 years in the household populations of Mexico and those of Mexican descent in the United States.
The results show that, compared to the general population of Mexico with no history of migration to the United States and Mexicans from migrant households who lived in Mexico until age 15, 11.5 percent of Mexican-American children with at least one U.S.-born parent met the DSM-IV criteria for conduct disorder. This level is similar to the non-Mexican-American, U.S.-born frequency of 10.6 percent.
“We found a striking epidemiological pattern with differences across generations that are both larger in magnitude and more narrow in scope that anyone expected,” said Joshua Breslau, a researcher with the RAND Corp. in Pittsburgh.
“Future studies will be needed to identify the specific environmental factors that contribute to these differences.”
The study appears in the December issue of the Archives of General Psychiatry, one of the JAMA/Archives journals.
Source: University of California