Childhood trauma associated with smaller hippocampal volume in women with major depression

Abstract

Objective: Smaller hippocampal volume has been reported only in some but not all studies of unipolar major depressive disorder. Severe stress early in life has also been associated with smaller hippocampal volume and with persistent changes in the hypothalamic-pituitary-adrenal axis. However, prior hippocampal morphometric studies in depressed patients have neither reported nor controlled for a history of early childhood trauma. In this study, the volumes of the hippocampus and of control brain regions were measured in depressed women with and without childhood abuse and in healthy nonabused comparison subjects.

Method: Study participants were 32 women with current unipolar major depressive disorder-21 with a history of prepubertal physical and/or sexual abuse and 11 without a history of prepubertal abuse-and 14 healthy nonabused female volunteers. The volumes of the whole hippocampus, temporal lobe, and whole brain were measured on coronal MRI scans by a single rater who was blind to the subjects' diagnoses.

Results: The depressed subjects with childhood abuse had an 18% smaller mean left hippocampal volume than the nonabused depressed subjects and a 15% smaller mean left hippocampal volume than the healthy subjects. Right hippocampal volume was similar across the three groups. The right and left hippocampal volumes in the depressed women without abuse were similar to those in the healthy subjects.

Conclusions: A smaller hippocampal volume in adult women with major depressive disorder was observed exclusively in those who had a history of severe and prolonged physical and/or sexual abuse in childhood. An unreported history of childhood abuse in depressed subjects could in part explain the inconsistencies in hippocampal volume findings in prior studies in major depressive disorder.

FIGURE 1. Representative MRI Showing Tracing of the Boundaries of the Right and Left Hippocampus in a Study of Hippocampal Volume and Childhood Physical and/or Sexual Abuse History in Women With Major Depressive Disordera

^a Structures included in the hippocampal volume were the gray matter of the hippocampus proper, the dentate gyrus, the subicular complex, the alveus, and the fimbria.

FIGURE 2. Volume of the Left and Right Hippocampal Head, Body, and Tail in Depressed Women With and Without a History of Childhood Physical and/or Sexual Abuse and in Healthy Comparison Subjectsa

^a For the whole left hippocampus volume, significant difference among groups (F=5.45, df=2, 36, p=0.009), between depressed women with and without a history of abuse (p=0.007, Tukey), and between depressed women with a history of abuse and healthy women (p=0.06, Tukey).