What is Transgenerational trauma?

Transgenerational trauma is the psychological and physiological effects that the trauma experienced by people has on subsequent generations in that group. There are two types of transmission: intergenerational transmission whereby epigenetic changes are passed down from the directly traumatized generation to their offspring , and transgenerational transmission when the offspring then pass it down to their offspring who have not been exposed to the initial traumatic event. Exposure includes when the offspring is in utero.

Collective trauma is when psychological trauma experienced by communities and identity groups is carried on as part of the group's collective memory and shared sense of identity. For example, collective trauma was experienced by Jewish Holocaust survivors and other members of the Jewish community at the time, and by the Indigenous Peoples of Canada during the Canadian Indian residential school system. When this collective trauma affects subsequent generations, it is called transgenerational trauma. For example, if Jewish people experience extreme stress or practice survivalism out of fear of another Holocaust, despite being born after the Holocaust, then they are experiencing transgenerational trauma.

Transgenerational trauma can be a collective experience that affects groups of people who share a cultural identity. It can also be applied to single families or individual parent–child dyads. For example, survivors of individual child abuse and both direct survivors of the collective trauma and members of subsequent generations individually may develop complex post-traumatic stress disorder.

The mechanism for transmission of trauma may be via epigenetic modifications introduced by stress. This is a novel area of research and given the complexity of issues surrounding trauma and the human experience, the relative contributions of epigenetics, cultural, and social factors will be challenging to elucidate.