Longitudinal study finds babies under 2 may be most at risk for long-term cognitive deficits

BOSTONApril 3, 2012 /PRNewswire-USNewswire/ -- Children exposed early in life to interpersonal trauma (maltreatment or witnessing partner violence against their mothers) have lower IQ-related scores at 2, 5 and 8 years of age, find researchers at  Boston Children's Hospital and the Institute of Child Development at the University of Minnesota. This deficit was highly significant after controlling for other strong predictors like socioeconomic status, the mother's IQ, birth weight, birth complications and the amount of cognitive stimulation received at home.

On average, children with such trauma exposure had cognitive scores that were about half a standard deviation lower than those not exposed – the equivalent of 7 IQ points. This effect is at least as great if not greater than the effects noted for lead exposure, says study leader Michelle Bosquet Enlow, PhD, in the Department of Psychiatry at Boston Children's Hospital.

"You can think of trauma as an environmental toxin similar to lead," Bosquet Enlow says. "Just as we need to eradicate lead exposure to protect IQ, we hope our results will spur efforts to identify families at risk and intervene to prevent this from happening. Maltreatment and violence exposure tend to be seen as criminal justice or social service issues, but they're also important public health issues."

The most significant and enduring cognitive deficits were in children exposed to trauma between birth and 2 years of age. "This is a very vulnerable time, when brain development is most rapid and thus particularly susceptible to the effects of environmental exposures, like violence. This is also the time when children are very needy and most likely to be abused," says Bosquet Enlow. "Those first two years have to be looked at very carefully."

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