A pilot longitudinal study of hippocampal volumes in pediatric maltreatment-related posttraumatic stress disorder

Abstract

Background: Adult posttraumatic stress disorder (PTSD) is associated with decreased hippocampal volumes; however, decreased hippocampal volumes were not seen in pediatric maltreatment-related PTSD. We examined hippocampal volumes longitudinally to determine if a history of childhood traumatic stress alters hippocampal growth during puberty.

Methods: Magnetic resonance imaging was used to measure temporal lobes, amygdala, and hippocampal volumes in nine prepubertal maltreated subjects with pediatric maltreatment-related PTSD and nine sociodemographically matched healthy nonmaltreated yoked control subjects at baseline and after at least 2 years follow-up (during the later stages of pubertal development) using identical equipment and measurement methodology.

Results: Temporal lobe, amygdala and hippocampal volumes did not differ between groups at baseline, follow-up, or across time.

Conclusions: Whereas these data are from a small sample, the results do not support hippocampal changes in pediatric maltreatment-related PTSD.

Introduction

Elevated levels of glucocorticoids during traumatic stress may be neurotoxic to the hippocampus, the principal neural target tissue of glucocorticoids (Sapolsky 2000). Smaller hippocampal volumes were reported in adults with Cushing’s syndrome (Starkman et al 1992), combat veterans with posttraumatic stress disorder (PTSD) Bremner et al 1995, Gurvits et al 1996, adult PTSD secondary to child abuse (Bremner et al 1997) and female adult survivors of childhood sexual abuse (Stein et al 1997). Severely maltreated but medically healthy prepubertal children with PTSD evidenced greater baseline urinary free cortisol concentrations than healthy control subjects (De Bellis et al 1999a). However, maltreated children and adolescents with PTSD did not show alterations in hippocampal volume compared with control subjects (De Bellis et al 1999b). In longitudinal brain imaging studies of healthy children and adolescents, temporal lobe cortical and subcortical gray matter and limbic system structural volumes (septal area, hippocampus, amygdala) show nonlinearly prepubertal increases and postpubertal volume decreases (Giedd et al 1999). Thus, one explanation for the differences in hippocampal findings between children and adults with PTSD is that childhood traumatic stress may stunt the normal pubertal growth of the hippocampus.

In this study, we longitudinally examined temporal lobes, amygdala and hippocampal volumes in nine prepubertal maltreated subjects with pediatric maltreatment-related PTSD and nine sociodemographically matched healthy nonmaltreated yoked control subjects at baseline and the later stages of pubertal development (at least 2 years follow-up). We hypothesized that hippocampal volumes would show greater decreases in the PTSD group compared with control subjects (i.e., that childhood traumatic stress would impede hippocampal growth during puberty).