Early life stress is a major risk factor for later episodes of depression [sciencedaily.com]. In fact, adults who are abused or neglected as children are almost twice as likely to experience depression.
Scientific research into this link has revealed that the increased risk following such childhood adversity is associated with sensitization of the brain circuits involved with processing threat and driving the stress response. More recently, research has begun to demonstrate that in parallel to this stress sensitization, there may also be diminished processing of reward in the brain and associated reductions in a person's ability to experience positive emotions.
Researchers at Duke University and the University of Texas Health Sciences Center at San Antonio looked specifically at this second phenomenon in a longitudinal neuroimaging study of adolescents, in order to better understand how early life stress contributes to depression.
They recruited 106 adolescents, between the ages of 11-15, who underwent an initial magnetic resonance imaging scan, along with measurements of mood and neglect. The study participants then had a second brain scan two years later.