Early life adversity is associated with brain changes in subjects at family risk for depression

The interplay of genetic and early environmental factors is recognized as an important factor in the aetiology of major depressive disorder (MDD). The aim of the present study was to examine whether reduced volume of hippocampus and frontal brain regions involved in emotional regulation are already present in unaffected healthy individuals at genetic risk of suffering MDD and to investigate whether early life adversity is a relevant factor interacting with these reduced brain structures.

Twenty unaffected first-degree relatives of patients with MDD (FHP: family history positive) and 20 healthy controls (FHN: family history negative) underwent high-resolution magnetic resonance imaging. Manual tracing of hippocampal sub-regions and voxel-based morphometry was used to compare groups and find association to early life adversity.

FHP subjects with history of emotional abuse had significantly smaller left and right hippocampal heads. VBM also showed smaller dorsolateral prefrontal cortices (DLPFC), medial prefrontal cortices (MPFC) and anterior cortex cinguli in FHP who had a previous history of emotional abuse.

High risk individuals for depression have reduced volume of brain regions related to emotional processing in particular when they additionally suffered childhood abuse, indicating that genetic and environmental factors like early life adversity influence brain structure possibly via epigenetic mechanisms and thus structural anomalies may precede the onset of the illness.