What trauma leaves behind
Trauma impacts mental health especially trauma in childhood. In a previous blog post I wrote about how kids who are poor are more likely to be exposed to trauma than wealthy kids. Now there is research that indicates that the effects of trauma can be biologically transmitted across generations. The researchers subjected mice to trauma in the laboratory in the form of electrical shocks. When baby mice were conceived using the sperm of the traumatized mice, the babies had a stress reaction to stimuli that were associated with their parents trauma, in this case a particular smell, and the effects seem to stretch over several generations. The theory put forth by the scientists to explain this is epigenetics, that certain genes are 'turned on' or 'off' by experiences creating heritable traits as a result of what happens in the environment.
If this carries over to humans, it could mean that a kid whose grandmother or grandfather experienced trauma could still carry the impact of that trauma in his or her body. My clinical experience is that trauma does seem to pile up in families. Sometimes the people who come into my office will describe three generations of abuse. It can be hard to get out from under that. Now we have another indicator of why that might be the case. Not only can there be a cultural inheritance of trauma in a family, the genetics of one's descendents can be marked by traumatic experiences.
On a more hopeful note, epigenetics may work to undo some the hurt of previous generations. Researchers here in Montreal, at the Douglas Hospital, have looked at the effect on an epigenetic level of nurturing by a parent on mediating stress (more traumatized rodents).
“Baby rats that are licked often by their mothers—with licking in rats fulfilling the same function as cuddling in humans—are calmer than rats that are not licked enough. Michael Meaney and his team delved further into this idea by tracking the imprint left by maternal care in the brain of young rats. They were able to do this because the action of licking influences the activity of a gene (called NRC31) that protects rats against stress; when activated, this gene produces a protein that helps decrease the concentration of stress hormones in the body. A specific part of this gene must also be activated via an epigenetic switch. ”
According to this theory loving cuddling can help kids deal better with stress than they might even if they have an epigenetic inheritance of trauma. So why are you still reading? Go hug your kids.