Can a Trauma be inherited?

An U.S. study of more than 50.000 women has recently brought a strange causality to light. “When a woman was the victim of severe sexual abuse as a child, the danger that she’ll later as a mother will give birth to a child suffering from autism increases by more than 60% (!) when compared to a non-traumatized woman. Our survey suggests that the fallout of childhood abuse resonates across generations,” says scientist Marc Weisskopf in an article published in the german magazine "Der Spiegel". The researchers included an impairment of the immune system and stress resistance of abused women as contributing factors as potential causes for the negative effect on the pregnancy and the embryonic development.

I found the results of this study extremely interesting – albeit not all that surprising. In my opinion at first glance they immediately, seamlessly and logically fall in line with a number of research findings on the subjects trauma and heredity that are also already responsible for a re-thinking in the field of psychotraumatology. Here the keyword is Epigenetics. Briefly summarizing, this covers a field of research dealing with the effects of environmental influences on the activity of our genes – and on those of our progeny. For the past 150 years evolutionary teaching was based on the theory that environmental influences and personal experiences are non-hereditary and only influence the individual. The opinion prevailed that only the parents’ genetic features and any associated features (as for instance eye- and hair color) but no traits that are only acquired by way of life’s experiences by the parental generations (as for instance a specific anxiety caused by traumatization) are passed on to the progeny. This conviction is now increasingly put to the test by Epigenetics’ research findings.
Here an example out of the laboratory: Scientists at Zurich University in Switzerland separated newly born mice early from their mothers and fed them just enough to survive. And who is surprised - the poor little, in the service of science abused animals exhibited behavior disorders as adults in that they were more anxious and depressed than their normally reared contemporaries. Not enough with that, surprise, surprise - not only did the abused generation of mice exhibit the already mentioned behavioral deficits, but it also passed its increased anxiety and depression on to its children! Although the latter were spoiled and fed the best stuff and were on the receiving end of the best food and ultimate care, they turned out to be just as anxious and depressed as their parents. Even the great-grandchildren of the original mouse children displayed increased anxiety levels. Ergo: The ancestral trauma was passed on.

Now the Epigeneticians are trying to figure out how this works. The mechanism is somewhat complicated: in summarizing, the individual gene is apparently biochemically activated and de-activated by “experiences” such as environmental factors, nutrition and personal experiences. To put it crudely, the genes feature something like an on/off switch and react according to external stimuli. Although the genetic code itself is not affected, while the epigenetic pattern appears to be. These influences act particularly aggressively beginning with the early embryonic development and continue as far as puberty. With increasing age the epigenetic pattern is more resistant to change i.e. the stimuli must then be stronger and more vigorous in order to generate an effect. Basically the pattern remains susceptible to change throughout life.

Subsequently these epigenetic changes have a bearing on the development of diseases, for instance. This is well documented in the case of cancer, but similar causal relations can also be proven in the case of mental disorders (for instance, at a Canadian university researchers were able to prove the impact of epigenetic changes on the emergence of severe depressions and suicidal tendencies). And as demonstrated by the animal tests demonstrated earlier, this impact does not merely effect the originally affected generation but also the following generations – it is being passed on to posterity.

Obviously one can’t very well put people into testing labs and ply them with food and contact deprivation to see whether that which works with mice, works with us as well. On the other hand, one can compile long-term studies over a period of years or decades and search in already accumulated massive amounts of data for comparable potential relationships. This happened at Bristol University, for instance. Here it was discovered that the children’s bodyweight is affected when the father had started smoking prior to his eleventh year: Those fathers’ sons where above average heavy. On the other hand, the father’ smoking had no comparable impact on the female offspring. A first indication that environmental effects are not only genetically passed on to the descendants but that even occurs gender specifically!
The same research team again corroborated this finding with the aid of a specific accumulation of data: For this, they consulted birth- and death data as well as information about certain ailments afflicting three generations in an area in the north of Sweden. They discovered an interesting pattern: If the boys in this region suffered from hunger between their 9th and 11th year due to a bad food supply (exactly the time when their spermatozoa began to mature), their male grandchildren later clearly fell ill from diabetes less often than the average population. On the other hand, children whose grandfathers never went hungry when young later died above average more often of strokes and other vascular diseases. The grandmothers also passed their hunger or non-hunger respectively in this form on to their grandchildren – albeit only to the girls.

It is clear that traumatic experiences such as hunger or sexual abuse do not only become a part of our memories and insinuate themselves into our soul but our gene pool, as well. In this way they therefore don’t only affect our very own life, health and personality but that of our children and children’s children, as well. An alarming insight but at the same time a truly exciting new beginning for therapeutic interventions. Compared to other branches of research Epigenetics are obviously still in the early stages. But it remains to be hoped that future generations may get a totally different perspective on many physical and psychological disorders where the origin according to today’s point of view is still classified as “ unexplained”. These days we are primarily still looking for the root of problems like depressions, addictions, autism or other psychological ailments in the life of the afflicted him/herself and at best in his/her immediate family and social environment. This approach may frequently simply be too limited. In order to truly comprehend the roots of their origin, maybe we should also turn to the past for an explanation.

Tags: Trauma, Epigenetics, sexual abuse, psychotraumatology