Stress experienced early in life is a potential risk factor for developing episodic depression later on. Adults who were subjected to abuse and neglect in childhood are about twice as likely to develop depression. Now, a recent study investigating the latter has revealed that childhood adversities are associated with the sensitization of brain circuits that process threat and drive stress responses.

More recently, evidence has surfaced suggesting that in along with sensitization to stress, the processing of reward in the brain is also diminished, and the ability to experience positive emotions is also reduced.

Investigating The Effects Of Early Life Stress On Brain Structure: What Causes Adulthood Depression?

Researchers at Duke University and the University of Texas Health Sciences Center at San Antonio conducted a longitudinal neuroimaging study to specifically analyze the relationship of early life stress and depression. They enrolled 106 adolescents between the ages of 11 and 15 who underwent an initial MRI (magnetic resonance imaging scan), along with measurements of mood and neglect. A second brain scan was then performed after two years.

The region of focus was the deep ventral striatum – a region important for processing rewarding experiences and creating positive emotions, both of which are lacking in depression. Their analyses revealed that over a period of two years (early to mid-adolescents), those who had been exposed to emotional neglect experienced an abnormal decrease in the response of the ventral striatum.

“More importantly, this decrease in ventral striatum response predicts the manifestation of depressive symptoms during this significant developmental period”, stated first author Dr Jamie Hanson. “These findings are consistent with other recent studies that show decreased or lacking reward processing in depression, and further highlight the importance of considering similar developmental pathways in an effort to protect individuals exposed to childhood adversities from developing depression later in their lives”.

Adulthood Depression: The Importance Of A Happy Childhood

The findings also suggest that in certain people, early life stress might compromise their capacity to experience pleasure and enthusiasm. Moreover, these stressors might increase with time, and individuals who initially appear normal may develop problems later.

“These insights are important since they suggest the existence of a neural pathway via which early life stress might contribute to the development of depression”, stated Dr John Krystal, editor of Biological Psychiatry. “Such a pathway could be potentially targeted by neural stimulation treatments. Moreover, the findings suggest that survivors of early life trauma, along with their families might benefit from learning about the possible consequences that might manifest later in life, which could help lead to an early intervention”.