Children who face extreme stress conditions are vulnerable to brain damage, suggests a study in the United States.
A study by Stanford University School of Medicine and the Lucile Packard Children's Hospital researchers says children with post-traumatic stress disorder suffered as a result of physical, emotional and sexual abuse, witnessing violence, or experiencing lasting separation and loss experience a reduction in the size of their hippocampus, that part of the brain necessary for memory processing and emotion.
For the study researchers examined 15 children suffering from PTSD in the ages 7 to 13 and measured the size of the hippocampus at the start and end of the 12- to 18-month study period.
The study threw up the finding that children with more severe PTSD symptoms and higher cortisol levels another stress indicator had higher reductions in the hippocampus than those with lower stress levels.
The significant aspect of the study, researchers found, was that the reduction in hippocampus size was in inverse proportion to the PTSD symptom severity and cortisol levels.
Researchers said it was a vicious cycle. Higher levels of the hormone cortisol led to a reduction in the size of the hippocampus, which makes it difficult for a child to handle trauma, and this in turns raises both stress and cortisol levels.
Researchers said similar effects have been noticed in animals previously, but this was the first time that it was being replicated in children.
Dr Victor Carrion, director of Stanford's early life stress research programme, said while normal stress levels are necessary for the brain's development, excess levels of stress can have a negative effect.
His group of researchers say children who are pre-programmed to anxiety either genetically or through the environment are also more prone to develop PTSD.
Carrion and his team are currently using an imaging technique called the functional MRI to see how the children's brain acts when performing emotional and cognitive duties. With further research, Dr Carrion more effective interventions can be found to help children suffering from PTSD.