Early Life Stress and Inherited Variation in Monkey Hippocampal Volumes

Abstract

SMALL HIPPOCAMPAL volumes are found in adult humans with recurrent major depression^1,2 and posttraumatic stress disorder.^3,4 Childhood stress increases the risk of developing these mood and anxiety disorders,⁵ and small hippocampal volumes are evident in adult survivors of childhood maltreatment.^6,7 Hippocampal morphology is altered by stress in carefully controlled studies of rodents,^8-11 and small hippocampal volumes in humans have been taken as evidence that stress-related disorders induce hippocampal volume loss.^2,11,12 An alternative possibility that cannot be dismissed in the absence of prospective longitudinal research is that small hippocampal volumes are inherited and predispose toward the development of psychiatric disorders that are triggered or aggravated by stress.^3,11