From mother to child. The role of epigenetic in the intergenerational trauma due to Intimate Partner Violence

Intimate Partners Violence (IPV) is characterised by several aggressive behaviours and controlling attitudes committed by intimate partners in different types of relationship. While gender, culture and traditions may influence different expression and experience of IPV, it affects both men and women with a higher representation in female gender. Advancement in epigenetic field may provide new insights about how an interaction between genes and   traumatic environment may promote DNA modifications, maintaining clinical pictures across the generations. In this framework, the traumatic experience of IPV may become intergenerational trauma. However, environment is highly involved by influencing the resilience and post-traumatic growth reactions to challenging situations. For these reasons, epigenetic markers may be involved as an early strategy of intervention as well as prevention campaigns in the context of IPV.

Article

Intimate Partners Violence (IPV) represents one of the most prevalent forms of violence against women and it’s characterised by several aggressive behaviours such as physical, sexual, emotional abuse and controlling attitudes committed by intimate partners in different types of relationship including married, dating and cohabiting couples ¹. In this perspective, each partners behaviour in the couple is used to maintain or gain power and control on the other ². Considering that up to 38% of the women’s murders across the world are committed by the intimate partner we can affirm that IPV is becoming a global phenomenon where culture and different country traditions influence the vision of hierarchy in women-men relation ³. Indeed, the patriarchal ideology may explain the significant prevalence of the phenomenon in countries where it is deeply settled, legitimizing abuse on women when they fail to conform to culturally acceptable behavioural norms ⁴. However, several risk factors may expose to IPV such as lower levels of education, witnessing family violence, childhood abuse, limited opportunity for women to access to paid employments ². In Italy, up to 50% of a 124 women sample who seek help at the Anti-Violence center in the last three-five years reported IPV ⁵ with the situation getting worse during Covid-19 Pandemic as cohabiting women increased their experience of IPV ⁶.

As the other side of the coin, men are in turn involved victims of IPV ^7,8. Obviously, gender, culture and traditions may influence different expression and experience of intimate violence, with psychological one hypothesized as the most common among male population ^7-8. According to national survey results reported from a Canadian study, 10.1% of men suffered from psychological or economic abuse from their current partner ⁹. Humiliation, having sexuality questioned, isolation from family and friends, being controlled and monitored, false accuse on child abuse are frequently revealed from male victims. Concerning physical violence, while it is less perceived due to the capability to restrain aggressive partners, male population often reported being coerced or pressure to have sexual act that would belong to a broader definition of sexual violence ⁷. In this perspective, contemplating or attempting suicide are frequent response to violence ¹⁰

Despite the literature focused on the psychopathological consequences of IPV ², knowledge on its long-term effects is still scarce. Repeated controlling behaviours continuously expose the subject to the traumatic event, leading to the development of a clinical picture ascribable to the complex post-traumatic stress disorder (c-PTSD) where post-traumatic symptoms are associated with an alteration in self-regulation: serious and persistent problems in the regulation of affections, beliefs about the self as diminished, defeated, or worthless, difficulty sustaining relationships and feeling close to others ^11-13. According to the concept of inter-generational trauma these symptoms and feelings may proceed through the generations interfering with the course of life of entire families and cultural group ^14,15. From an epigenetic point of view, the interaction with environment, specifically with traumatic environment, may lead to stable changements in DNA inducing molecular adjustment passing across further generations not present at the moment of IPV episodes ^16,17. Focusing on the three principal disorders caused from IPV exposure, anxiety, depression and PTSD, several authors highlighted the presence of epigenetic changesets related to neurotrophins underlying long term effect of these clinical pictures ². Noteworthy, the severity of maternal anxiety due to childhood domestic violence is deeply related to foetal brain derived neurotrophic factor (BDNF) methylation, important neuronal growth factor involved in the pathophysiology of suicidal behaviours and anxious- depressive features, as well as PTSD ¹⁸. At the same time IPV showed a significant correlation with methylation of insulin growth factors 2 (IGF-2) implicated in human evolution since the foetal phase and described in several disorders such as bulimia and anorexia, alcohol related disorders, PTSD and Schizophrenia ^2-19. Finally, epigenetic modification of NRC3 gene, following mothers IPV exposure, interfere with physical development such as alterations in newborn weight associated to depressive and anxious pictures ^2,20.

To date, a growing field of literature is providing new insights on how environment/gene interactions shaping epigenetic changes may lead to different trauma reactions such as resilience and post traumatic growth ²¹. In the context of IPV, the presence of positive self-perceptions, optimistic life perspectives, and a hopeful view of the future allows women to cope with high challenging situations deriving from intimate violence ²². Moreover, cPTSD symptoms often occurring in the victims are probably mitigate through high levels of resilience ²³. In addition, a deeper understanding on this phenomenon may come from epigenetic evidence ²⁴. Indeed, some authors report that when maternal exposure is present after pregnancy, children experience similar psychiatric problems to their mothers. Conversely, when IPV occurred during or before pregnancy the methylation of glucocorticoid receptor (NR3C1) and its repressor FKBP51 (FKBP5) seem to enhance stress response in the newborn ²⁴. For this reason, some authors hypothesize to employ epigenetic variations in neuroplasticity genes, BDNF, IGF-2, DR2 in association to early strategies of detection for addressing women towards resilience ²⁵.

In conclusion, IPV represents a timely and global phenomenon affecting both men and women with a higher prevalence in female gender ^7,8. The resulting psychopathological consequences may lead to the onset of anxious, depressive and PTSD features². Moreover, advancement in epigenetic field may provide new insight about how an interaction between genes and traumatic environment may promote DNA modifications passing from mother to child, maintaining clinical pictures across the generations^14-15. In this framework, the traumatic experience of IPV may become intergenerational trauma. Globally, environment is highly involved by influencing the reaction to challenging situations, from which not only different psychological trajectories but also resilience and post-traumatic growth may develop¹⁴. For these reasons, epigenetic markers may be involved as an early strategy of intervention as well as prevention campaigns to break the chain of IPV trans-generational trauma.

Funding

This research did receive no external funding.

Conflict of interest statement

The authors declare no conflict of interest.

Authors contributions

Conceptualization: LDO and BC. Methodology: LDO, BC, BN, CB.Investigation: BN, CB. Original draft: BN, CB. Writing - review & editing: BC and LDO.