Genetic transfer of physical and mental qualities is an established fact, but there is now a new idea gaining traction: intergenerational trauma. The simplest definition of intergenerational trauma is the recognition that exposure to extremely traumatic events affects people to such an extent that their offspring struggle to understand their parents’ post-traumatic state.
A more recent and provocative theory suggests that trauma itself, or rather its effect, is somehow “passed” on from one generation to the next through non-genomic, potentially epigenetic mechanisms affecting gene transcription. Genes may be “expressed” or their characteristics noted, or they may be “silenced.”
The crucial question is whether or not extreme stress or trauma transforms genes or their expression or silencing in some way and passes those changes down to children. Lamarck was ridiculed when he suggested that, for example, giraffes had long necks because their genes had somehow been affected (he didn’t specifically mention genes) by stretching up to trees for food and that this produced offspring with long necks. More likely, those with longer necks survived and reproduced (that’s Darwin’s natural selection), but was there an inherent gene selection or something else at work? Now Lamarck is being reconsidered and behavioral change is up for reconsideration.
There is growing evidence that experiences from both parents and ancestors, such as diet, exposure to pollutants in the environment, nurturing behaviors, and social stress, can have significant impacts on an organism’s physiological, metabolic, and cellular functions. Under some conditions, these impacts can be passed down through multiple generations via modifications that are epigenetic (i.e., not based on mutations but on non-DNA sequences). Male and female offspring of defeated fathers show higher levels of various behaviors associated with anxiety and sadness. But what about defeated mothers? If the trauma is transmitted biologically, might the same apply? The research is ongoing.
Work with the children of Holocaust survivors has shown interesting results. Adult children of Holocaust survivors have shown distinct impacts of both parental and maternal posttraumatic stress disorder (PTSD) on glucocorticoid receptor sensitivity and susceptibility to psychiatric disorders.
Researchers are exploring how stress and trauma may make brain changes that will affect future generations. If this proves to be true, then stress and trauma management may need both present and future treatments to address these negative changes before they can affect the lives of children. Can AI be of assistance in designing methods that are more effective in extreme cases of trauma?
If trauma and high stress are subsumed here and affect the parent, will the children also carry markers or behavioral indicators for this change brought about by the parental trauma? It seemed so in the research with the children of Holocaust survivors. The answers are now clear, and studies exploring this connection are vital since trauma is so destructive to many individuals.
Yes, there are degrees of response to trauma, and, therefore, we would expect a continuum of heritability, if we can use that term now, in the children of these parents. Also, we cannot ignore the effects of modeling on children who live with traumatized parents. So, the questions remain many, and the answers are still few and not established in theory, only hypotheses.
As has been shown in multiple studies, vicarious trauma exists and trauma does not need to be experienced directly, and it is here that research might need to focus a bit more. What of the adults or children who “experience” the trauma virtually via video or other forms of media? Even healthcare professional are affected by this indirect trauma. Difficult to prove, surely, but worthy of continued consideration.
I’m not a biologist, but the question is intriguing to me and, I assume, to others as well.