Genetic Generational Transmission of Trauma: Is It Real?

The Holocaust. World War II. Domestic violence. Child sexual abuse. All of these traumatic experiences leave visible and invisible marks on the survivors. In addition, these survivors may have epigenetic marks left on the chemical coating on their chromosomes. Some call it a biological memory of the trauma. According to the Veterans Affairs’ National Center for PTSD, approximately 8% of trauma survivors will eventually develop post traumatic stress disorder (PTSD). These people seem to have greater vulnerabilities to stress than the general population. Past studies suggest that the vulnerabilities are due to environmental factors like how the person was raised as a child.

However, new research is shedding light on the potential for transgenerational effects that might be transmitted genetically to children. Studies in epigenetics are pointing to both environmental and hereditary factors to explain the transgenerational transmission of trauma, which adds a layer to the understanding of psychobiological dimensions. In short, epigenetics may lead to clearer data on why latent transmission manifests itself when an individual experiences unusual stress.

Research is suggesting that children of parents with PTSD, from whatever cause, may be more vulnerable to developing inappropriate responses to stress. The individuals experiencing PTSD may be survivors of combat, refugees, victims of childhood sexual abuse, torture, or other extreme forms of stress. And, studies are suggesting that genetic transmission may go beyond the next immediate generation, impacting grandchildren and great grandchildren as well.

Academic literature has described transgenerational transmission of trauma (TTT) for about the last 50 years, and TTT specifically looks at heredity and the potential to transmit trauma characteristics from parents to children. At least 500 studies have been published on the subject. Yet, we are still unclear on how the unconscious trauma of a parent with PTSD may be genetically passed on to a child. The idea itself does not present any clear, logical hypotheses. Are forgotten memories passed on generation to generation? Can any neurobiological evidence exist that scientifically proves that the phenomena is real, such as an MRI scan or a blood specimen?

While science is still unclear on TTT, new research suggests that traumatized parents may produce children with an increased disposition to PTSD if subjected to extreme stress. Twin and family studies have pointed to an underlying genetic component and as much as 30% of that component may be due to an inheritable trait.