Chronic stress in the first few years of life — like that from abuse, neglect or poverty — can have a lasting impact on the developing brain, according to new research.
Toxic stress at an early age may critically affect memory, learning and the way emotions are processed, finds a study published in the journal Biological Psychiatry.
The research investigated exactly why early life stress can lead to such a wide range of negative outcomes later in life, including depression, anxiety, poor educational achievement and also physical problems (Hanson et al., 2014).
Seth Pollak, co-leader of the study, said:
“We haven’t really understood why things that happen when you’re 2, 3, 4 years old stay with you and have a lasting impact.
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.”
The researchers recruited 128 children at around the age of 12 who had experienced neglect, abuse or other serious, chronic stressors in the first few years of their lives.
The children and their caregivers were interviewed about their early life experiences and any behavioural problems they now had.
Their brains were also scanned, with a special focus on the hippocampus and amygdala, both of which are heavily involved in how the brain processes emotions.
The results from these children were compared with other children from middle-class backgrounds who had not been maltreated.
What emerged was that those who had suffered chronic stress in early life had smaller amygdalas than those who had not.
In addition, those who were from very poor backgrounds or who had been physically abused also had smaller hippocampi.
While the implications of the reduced size of the amygdala is unknown, a smaller hippocampus is a recognised risk factor for negative outcomes.
Unsurprisingly the children who’d suffered early life stress also had more behavioural problems, and the smaller the affected brain structures were, the greater the behavioural problems.
Seth Pollak said:
“For me, it’s an important reminder that as a society we need to attend to the types of experiences children are having.
We are shaping the people these individuals will become.”
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Image credit: Runar Pedersen Holkestad