New research in neuroscience and genetics may reveal why some people react more sensitively to emotional stimuli than others. A study recently published in The Journal of Neuroscience by Rebecca Todd, Adam Anderson, and others at the University of British Columbia indicates that carriers of a particular genetic variation perceived both positive and negative images more vividly than those without the variant, evidenced in increased activity in particular regions of the brain (see below, from medicalxpress).
The gene, ADRA2b, influences norephinephrine (a neurotransmitter). Todd, Anderson, et al have discovered that “carriers of a deletion variant of this gene showed greater attention to negative words.” The increased activity in sections of the brain which regulate emotions and help establish “pleasure and threat” by such carriers might explain why some people are more susceptible to PTSD and other stress-related illnesses. How we feel about the world around us is influenced by how our brains perceive the world, so those who experience good and bad aspects more vividly may react more than the average person.
It’s not all bad, though. Todd suggests that having this variant could be beneficial because these additional networks assist in our calculation of the “emotional relevance of things” and this could be a major factor in survival. The researchers point to the writer, Marcel Proust, who wrote 7 volumes of memoirs after tasting a cookie as a prime example of what researchers call EEV–“emotionally enhanced vividness.” In his case, the pleasure of a Madeleine treat was so enhanced that it triggered his prolific prose.
While more study is needed to determine whether the presence of EEV falls along specific racial and gender lines, this UBC study revealed that about 50% of Caucasians carried the gene variation, compared to only 10% of Rwandans. This opens an exciting possibility for better treatment of those who seem to be “too sensitive” (source: http://www.medicalxpress.com).
In another study released in the same month, we learn that researchers at Wellcome Trust Centre for Human Genetics have discovered that depression and prolonged illness wreak havoc on our DNA as well as our bodies and minds. By looking at the genomes of 11,500 women they found that women with stress-related depression—the kind associated with childhood adversity such as abuse—had more mitochondrial DNA (mt DNA) than mentally and emotionally healthy peers. Mitochondria are the power generators and an increase in their number indicates that the cells had increased energy needs due to depression or chronic illness (source: Alap Naik Desai, “Depression Can Alter Our DNA…,” http://www.inquisitrnews.com). So, while some genes may cause us to be more sensitive to external stimuli, negative stimuli (such as childhood abuse) can change our bodies, minds, and our DNA! And that leads to a final study that is causing quite a stir in the scientific community.
Ongoing studies show that some children and even grandchildren may have a “biological memory” in their DNA of stresses faced by their parents/grandparents. A new scientific field, called “epigenetic inheritance,” suggests that some genes from past generations can be switched on or off, depending upon environmental factors such as trauma, stress, and prenatal nutrition. The most famous example of this is in the research of the offspring of Holocaust survivors who continued to suffer terrible nightmares of being “’chased, persecuted, tortured, or annihilated’” leading to debilitating anxiety, dread, and depression. Survivors of such horrors as the Nazi Holocaust were so damaged by their experiences that it actually changed their DNA. Their children and even grandchildren somehow inherited their forebears’ repressed trauma. Similar ‘scars’ on DNA have been passed on to children whose mothers witnessed the 9/11 attacks on the WTC. Knowing about the sources of their parents or grandparents’ trauma might help current sufferers to deal with this internalized trauma. (source: Vivian Giang, “How Your Grandparents’ Lives Affect Your Resilience to Stress,” http://www.fastcompanty.com). This inter-generational trauma may begin to explain why some families continue to relive and/or perpetuate the horrors visited upon them. The old biblical curse of the “sins of the fathers visited upon the sons” would seem to have some psychological validity in view of these recent epigenetic studies. Perhaps therapists should rethink clinical approaches to patient treatment in light of the reality of abuse or trauma actually changing our DNA, passing it down to our children and grandchildren.