Child Abuse (CA) is defined as physical, emotional, or sexual maltreatment / neglect of a child. It has long-lasting effects on the brain and devastating consequences on psychological development. 1 in 3 Canadians experience maltreatment before the age of 15. It is one of the strongest predictors of depression and suicide. Currently, 300 million people are suffering from Major Depressive Disorder (MDD) and it is the leading cause of disability worldwide. Those who have MDD and suffered from CA are more likely to have more severe diagnoses, recurrent episodes and be resistant to treatment. Why is this? What’s happening in our brains during child abuse, that leads to these negative consequences later in life? We don’t really know. Some studies show us that there are differences in the way our neurons communicate after severe abuse in childhood, but there is still a lot to learn–and that’s where I come in.
We know that childhood and adolescence are critical periods of plasticity, during which the brain is very malleable, and connections can change pretty easily. During this time, our brain is very sensitive to things happening in our external environment–more so than in adulthood. The things that close this critical period, and make our brain less plastic, are these beautiful things I study, called perineuronal nets. These nets (red in the image below) are mesh-like structures made of proteins and sugars, that literally form a net around certain cells in the brain. They’re there to protect the cell they enwrap and concretize the connections it has with other cells around it–hardening the brain and closing the critical period of plasticity.
We believe that child abuse occurring during the critical period of plasticity is altering the way these nets develop, especially in areas of the brain involved in regulating emotion. So, we took brains from those who have died by suicide, were diagnosed with depression, and were either abused as children or not. I sliced the tissue, stained it and visualized these nets in the brain–as you can see here. We found that there is an increase in the number of nets in a specific area of the brain in depressed suicides, but especially those who were abused as children. So the idea is that, while the child is being abused, they are developing maladaptations, which are concretized by the increased recruitment of these nets (because they’re there to stabilize connections in the brain). Then those bad habits are long lasting–and may help explain why child abuse is so correlated with depression and suicide.
The need to understand what effects child abuse has on people is extremely important, as it can influence things like public policy and parenting in general.
By: Claudia Belliveau