Extreme stress experienced during childhood, such as poverty, neglect, and physical abuse, might alter the parts of the brain responsible for learning, memory, and the processing of stress and emotion.
These changes may be linked to negative effects on behavior, health, employment, and even the choice of romantic partners later in life, according to researchers from the University of Wisconsin-Madison.
“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,” said Dr. Seth Pollak, co-leader of the study and UW-Madison professor of psychology.
“Yet,” noted Pollak, “early life stress has been linked to depression, anxiety, heart disease, cancer, and a lack of educational and employment success.”
“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,” said Pollak, also director of the UW Waisman Center’s Child Emotion Research Laboratory.
The study involved 128 children, approximately age 12, who had experienced either physical abuse, neglect early in life, or came from low socioeconomic status.
The children and their caregivers underwent in-depth interviews, reporting behavioral problems and their cumulative life stress. The researchers also took images of the children’s brains, focusing on the hippocampus and amygdala, parts of the brain involved in emotion and stress processing. These images were compared to similar children from middle-class households who had not been maltreated.
The researchers outlined each child’s hippocampus and amygdala by hand and calculated their volumes. Both brain structures are very small, especially in children, and the researchers believed that automated software measurements might be prone to error.
The findings showed that children who experienced any of the three types of early life stress had smaller amygdalas than children who had not. Children who lived in poverty and children who had been physically abused also had smaller hippocampal volumes.
Putting the same images through automated software showed no effects. Behavioral problems and increased cumulative life stress were linked to smaller hippocampus and amygdala volumes.
“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.”
But the findings, say the researchers, are only markers for neurobiological change — a display of the robustness of the human brain, and not a crystal ball to be used to see the future.
“Just because it’s in the brain doesn’t mean it’s destiny,” said study author and UW Ph.D. graduate Jamie Hanson.
The study is published in the journal Biological Psychiatry.
Source: University of Wisconsin-Madison