Mexican government program that offers assistance to families living in extreme poverty if they comply with certain conditions, improves not only children's health but also their behavior, researchers have found.

The "conditional cash transfer" program called Oportunidades, initiated by the Mexican government in 1997 in 506 very poor rural communities, gives impoverished families cash in exchange for attendance at school and medical check-ups and consumption of provided nutritional supplements.

Brazil, Argentina, Nicaragua and other middle- and lower-income countries are now using conditional cash transfer programs based on evidence that these programs can make a difference in the health of participating families.

Dr. Emily J. Ozer from University of California, Berkeley, and colleagues now report in journal Pediatrics that these programs also seem to help curb behavior problems in young children.

They compared parental reports of behavior in 702 children from households involved in the cash transfer program for up to 5 years with parental reports on 263 children from other poor rural communities not currently involved in the program. The average age of the children in the study was 5 years.

After factoring in a range of child and family characteristics that might influence the results, researchers found that participation in the conditional cash assistance program was associated with a modest decline in aggressive and "oppositional" behavior problems in both boys and girls.

"Our findings," Ozer and her colleagues conclude, "suggest that interventions that invest in basic human capital needs may exert longer term ripple effects on children's development."

"Although the Oportunidades program demonstrated only a modest effect on aggressive/oppositional symptoms," they note, "extensive research on conduct problems in high-income countries suggests that even small differences early in development can magnify over time to influence children's developmental trajectory."