Background Childhood trauma exposure has been associated with deficits in cognitive functioning. The influence of timing of exposure on the magnitude and persistence of deficits is not well understood. The impact of exposure in early development has been especially under-investigated. This study examined the impact of interpersonal trauma exposure (IPT) in the first years of life on childhood cognitive functioning.

Methods Children (N=206) participating in a longitudinal birth cohort study were assessed prospectively for exposure to IPT (physical or emotional abuse or neglect, sexual abuse, witnessing maternal partner violence) between birth and 64 months. Child intelligent quotient (IQ) scores were assessed at 24, 64 and 96 months of age. Race/ethnicity, gender, socioeconomic status, maternal IQ, birth complications, birth weight and cognitive stimulation in the home were also assessed.

Results IPT was significantly associated with decreased cognitive scores at all time points, even after controlling for socio-demographic factors, maternal IQ, birth complications, birth weight and cognitive stimulation in the home. IPT in the first 2 years appeared to be especially detrimental. On average, compared with children not exposed to IPT in the first 2 years, exposed children scored one-half SD lower across cognitive assessments.

Conclusion IPT in early life may have adverse effects on cognitive development. IPT during the first 2 years may have particular impact, with effects persisting at least into later childhood.