Amygdala and Hippocampal Volumes in Familial Early Onset Major Depressive Disorder

Abstract

Abnormalities in the amygdala and hippocampus have been implicated in the pathogenesis of major depressive disorder (MDD). To our knowledge, no prior study has examined amygdala-hippocampus anatomy in pediatric patients with familial MDD (at least one first degree relative with MDD). Thirty-two psychotropic-naive patients with familial MDD, aged 8-21 years (12 males and 20 females), and 35 group-matched healthy participants (13 males and 22 females) underwent volumetric magnetic resonance imaging in order to evaluate hippocampal and amygdala volumes. Patients with familial MDD had significantly smaller left hippocampal (p = .007, effect size [d] = .44) and right hippocampal volumes (p = .025, d = .33) than controls. No differences were noted in amygdala volumes between groups (right: p > .05, left: p > .05). No correlations between hippocampal or amygdala volumes and demographic or clinical variables were noted. Reduced hippocampal volume may be suggestive of a risk factor for developing MDD.