Toronto: Children who suffer severe abuse experience changes in the neural structures in specific areas of the brains, scientists have found for the first time.
Difficulties linked with severe childhood abuse include increased risks of psychiatric disorders such as depression, as well as high levels of impulsivity, aggressivity, anxiety, more frequent substance abuse, and suicide.
For the optimal function and organisation of the brain, electrical signals used by neurons may need to travel over long distances to communicate with cells in other regions.
The longer axons of this kind are generally covered by a fatty coating called myelin. Myelin sheaths protect the axons and help them to conduct electrical signals more efficiently.
Myelin builds up progressively - in a process known as myelination - mainly during childhood, and then continue to mature until early adulthood.
Earlier studies had shown significant abnormalities in the white matter in the brains of people who had experienced child abuse.
However, because these observations were made by looking at the brains of living people using MRI, it was impossible to gain a clear picture of the white matter cells and molecules that were affected.
Researchers McGill University in Canada compared post- mortem brain samples from three different groups of adults - people who had committed suicide due to depression and had a history of severe childhood abuse (27 individuals); people with depression who had committed suicide but had no history childhood abuse (25 individuals); and people who had neither psychiatric illnesses nor a history of child abuse (26 people).
The researchers discovered that the thickness of the myelin coating of a significant proportion of the nerve fibres was reduced only in the brains of those who had suffered from child abuse.
They also found underlying molecular alterations that selectively affect the cells that are responsible for myelin generation and maintenance.
The researchers concluded that adversity in early life may lastingly disrupt a range of neural functions in the anterior cingulate cortex.
