Neighborhood deprivation affects children's mental health: environmental risks identified in a genetic design.

The possibility that neighborhood conditions affect children's development has captured much attention because of its implications for prevention. But does growing up in deprived neighborhoods matter above and beyond a genetic liability to behavior problems, if genetically vulnerable families tend to concentrate in poor neighborhoods? A nationwide study of 2-year-old twins shows that children in deprived neighborhoods were at increased risk for emotional and behavioral problems over and above any genetic liability. Environmental factors shared by members of a family accounted for 20% of the population variation in children's behavior problems, and neighborhood deprivation accounted for 5% of this family-wide environmental effect. The results suggest that the link between poor neighborhoods and children's mental health may be a true environmental effect, and demonstrate that genetic designs are environmentally informative and can be used to identify modifiable risk factors for promoting child health.