A longitudinal study uncovers the lifelong consequences of child abuse and exposure to interpersonal conflict in the first two years of life.

PROBLEM: Though previous research has linked emotional trauma to problems in cognitive functioning, little is known about the impact of domestic violence and abuse on the intellectual development of infants.

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METHODOLOGY: Researchers led by Michelle Bosquet Enlow tracked 206 children since birth who were taking part in a longitudinal study that looks at factors that influence individual development. They analyzed data on mother-child interactions at home and in the lab, interviews with the mother, and medical and child protection records to determine whether a child was abused physically, sexually or emotionally; endured neglect; or witnessed partner violence against his/her mother. They also assessed each kid's scores in cognitive tests taken at the ages two, five, and eight.

RESULTS: Children who were abused or had witnessed violence against their mother had lower scores on the cognitive measures at all time points, and this effect was strongest among those who were traumatized during the first two years of their lives. Their IQ scores were an average of 7.25 points lower than those of children without early exposure, even after accounting for known risk factors, such as social and economic factors, mother's intelligence, weight at birth, birth complications, and quality of intellectual stimulation at home.

CONCLUSION: Emotional trauma during infancy may do permanent harm on a person's intelligence.

IMPLICATION: The authors note that their findings echo past studies involving early-life trauma and adversity that have identified changes in brain circuitry and structure. They write: "Because early brain organization frames later neurological development, changes in early development may have lifelong consequences."

SOURCE: The full study, "Interpersonal Trauma Exposure and Cognitive Development in Children to Age 8 Years: A Longitudinal Study," is published in the Journal of Epidemiology and Community Health.