"Childhood maltreatment is associated with reduced volume in the hippocampal subfields CA3, dentate gyrus, and subiculum"
childhood trauma causes measurable physical biochemical changes to children.
according to a study published by the national academy of sciences. http://www.pnas.org/content/109/9/E563
with supporting data here http://www.pnas.org/content/suppl/2012/02/07/1115396109.DCSupplemental/pnas.201115396SI.pdf
and author summary http://www.pnas.org/content/109/9/E563/1
Childhood maltreatment or abuse is a major risk factor for mood, anxiety, substance abuse, psychotic, and personality disorders, and it is associated with reduced adult hippocampal volume, particularly on the left side. Translational studies show that the key consequences of stress exposure on the hippocampus are suppression of neurogenesis in the dentate gyrus (DG) and dendritic remodeling in the cornu ammonis (CA), particularly the CA3 subfield.