Stress during childhood can have lasting negative impacts on the brain.
A team of University of Wisconsin-Madison researchers showed stressors such as "poverty, neglect and physical abuse" can change parts of the child's brain associated with "learning, memory and the processing of stress and emotion."
"We haven't really understood why things that happen when you're [two], [three], [four] years old stay with you and have a lasting impact," Seth Pollak, co-leader of the study and UW-Madison professor of psychology said.
Stress early in life has been tied to "depression, anxiety, heart disease, cancer, and a lack of educational and employment success" in the past.
"Given how costly these early stressful experiences are for society ... unless we understand what part of the brain is affected, we won't be able to tailor something to do about it," Pollak said.
To make their findings the team looked at 128 children who were about the age of 12 and had come from abusive homes or poverty.
The team conducted interviews with the children and their caregivers to asses their cumulative stress. They also took images of the children's brains, especially focusing on the hippocampus and amygdala because they are associated with emotions and stress processing. The team found that children who had experienced any of those three types of stress had smaller amygdalas than those who had not. Children who had been physically abused or came from poverty also had smaller hippocampal volumes. Behavioral problems as well as increased cumulative life stress were also linked to smaller hippocampus and amygdala volumes.
The researchers are not sure why early life stress leads to smaller brain structures.
"For me, it's an important reminder that as a society we need to attend to the types of experiences children are having," Pollak said. "We are shaping the people these individuals will become."
