Stressful or traumatic experiences occurring in a child’s earliest years—birth to age 5—have been linked to reduced hippocampal volume in adolescence, according to a new US Vanderbilt University report published in Developmental Science Journal, reported Ajman News.

“These findings tell us that there may be a ‘sensitive period’ in which stress is more likely to affect the development of the hippocampus, which is connected to learning, memory and mood,” said lead author Kathryn L. Humphreys, assistant professor of psychology at Vanderbilt.

“Given that the hippocampus undergoes rapid changes in the first years of life, the effects of stressful experiences during this period, even those the child doesn’t remember, may be particularly important in understanding the development of this region of the brain.”

In the study, 178 early adolescents underwent structural magnetic resonance imaging. They were interviewed using a modified version of the Traumatic Events Screening Inventory for Children.

More than 30 different stressors were examined, including parental divorce, moving to a new community, separation from a loved one, illness or death of a close friend or family member, witnessing violence and experiencing abuse.