Stress and the saddest moments are increasing worldwide as years go by. We have started to lose our grandmothers, and grandfathers who attended wars, or migration. Even if we have a perfect life, houses, education, and families, we may have psychological issues, and fears. Have you ever wondered why we are like this and have down our self-esteem? May the grand one in our family gives us a heritage.
Traumas can be occurred because of natural disasters, being abused physically, emotionally, or sexually, migration, war, and terror. Traumas separate into two types: acute and chronic. Post-trauma-stress-disorder can be developed after trauma. PTSD has three main symptoms: re-experiencing, avoidance, and overstimulation1. On re-experiencing, the patient has dreams about the trauma and pain or flashbacks. Also, they show deep psychological and physical reactions to traces that come from inside and outside. On avoidance, the patients escape from individuals and places that make them remember the trauma. In addition, they have numbness of emotions and decreased interest in something1.
Not-treated PTSD may be a cause of major depressive disorder and dissociative disorders1,2. If we need to give brief information about dissociative disorders, another one or more personalities occur from time to time. These personalities control individuals’ life for a short or long time. Also, the personalities do not recognize each other and slip from one to another personality1,2.
Franz Ruppert, a psychologist, says that especially childhood traumas inside of family living create a permanent trauma typology2. According to him, three types of traumatic experiences pass the next generations with attachment patterns: existential trauma, the trauma of loss, and the trauma of the attachment system2. Traumatic effects can be varied even if individuals experience the same trauma. The reason for that is differences in biological processes, genetics, and epigenetics of individuals4.
Most studies on PTSD are about genetics. For this research subject, twin studies are precious. The degree of similarity in traits between monozygotic and dizygotic twins is compared4. The genes are selected based on earlier studies of PTSD from etiologic, pathologic, or neurologic perspectives. Until 2016, more than 25 genes have been examined. For detailed information, the reference of this paragraph can be used4.
In this article, epigenetic differences will be given. First, let’s meet with HPA. The system that answers to major neuroendocrine stress is called the hypothalamic pituitary adrenal axle (HPA)3,6. This system is examined in PTSD patients. Stress goes through the hypothalamic paraventricular nucleus (PVN) and makes corticotropin-releasing factor (CRF) release from the amentia medial to the hypothalamus-pituitary portal circulation3. Adrenocorticotropin is released by the front pituitary gland. This enzyme induces glucocorticoid release from the adrenal cortex. Glucocorticoids organize physiological functions and behaviors against stress factors3,6. These physiological functions can be changing blood pressure, heart rate, and glucose metabolism6. A detailed infographic is given below. Being exposed to glucocorticoids continually decreases dendritic branching, decreases neurogenesis, and be causing loss of dendritic spines. Briefly, childhood stress and trauma affect the HPA axis. Long-term dysregulated HPA axis can increase the risk of health6.

A nucleosome is a fundamental subunit of the structure of chromatin3. The duality of DNA and histone proteins is called histone octamers. Epigenetic mechanisms edit gene expressions by controlling the frequency of nucleosomes. If the chromatin structure is tight, silent genes will be inactivated. If the chromatin structure is loose, then the genes will be activated3. These situations in chromatin structure can be arranged by DNA methylation and histone modifications. These are epigenetic patterns or mechanisms which are changes in gene expression that occurred by non-mutation factors3,5,6. Epigenetic changes are heritable, but they can be recyclable3. A diagram of epigenetic mechanisms is given below. The most related to intergenerational traumas are histone modifications-especially acetylation and DNA methylation3.
In DNA methylation, to specific gene regions which are cytosine residues, methyl groups are added3. This situation changes the DNA function and inhibits the transcription of the gene. Active chromatin is less methylated3,5. DNA modifications are important for the nervous system and can change in pathological conditions3.
In histone modifications, especially histone acetylation is related to the condition of fear. Negatively charged acetyl groups attach to lysin residues of histone proteins. Histone Acetyl Transferase (HAT) and Histone Deacetylase (HDAC) play opposite roles in histone acetylation. Histone acetylation decreases electrostatic recession and gene expression gets easier because of the structure of chromatin3.

Histone acetylation and other modifications of it; methylation, deacetylation, and demethylation can silence specific genes or play roles of activation of them. Also, specific modifications of histones can be a marker to determine active or inactive genes as transcriptional3.
On the other hand; the psychological perspective and the effects of the trauma for at least three generations are quite important. Children who grew up with parents who have PTSD can affect by their parents’ struggle. Their parents are the first generation. The effects of trauma on the first generation may be symptoms that lead to high levels of emotional and psychological disorders. First-generation survivors have high levels of depression and anxiety for fear of not giving a safe environment to their children. Children hold the past and include their parents’ anxiety because of that. For the second generation, living with trauma survivors can cause continuous stress. So, the families of the second generation can be traumatized. Because of that situation, they can have enmeshed dependency, issues of emotional expression, also high levels of guilt, frustration, and anger according to clinical studies7.
For the third generation, there is not enough research. When one study shows the third generation of Holocaust survivors goes to child psychiatry services, another one shows they are not different from the control group for anger issues. The work of Berger-Reiss suggests epigenetic contribution by showing examples that the symptoms of hidden trauma from two generations before the third generation and their resistance to the therapy. This concludes the evidence of the epigenetic view of intergenerational traumas7.
References:
- (PDF) Travma, Dissosiyasyon ve Hafıza: Teorik ve Epigenetik Bir Yaklaşım Trauma, Dissociation and Memory: A Theoretical and Epigenetic Approach. (n.d.). Retrieved August 26, 2022, from https://www.researchgate.net/publication/361261943_Travma_Dissosiyasyon_ve_Hafiza_Teorik_ve_Epigenetik_Bir_Yaklasim_Trauma_Dissociation_and_Memory_A_Theoretical_and_Epigenetic_Approach
- ÖZTÜRK, E., & DERİN, G. (2015). Psikotravmatoloji Psychotraumatology. Aydın İnsan ve Toplum Dergisi, 6(2), 181–214. https://doi.org/10.17932/iau.ait.2015.012/ait_v06i2003
- ACET GÖKÇE N.,2017, Travma Sonrası Stres Bozukluğunda Epigenetik Değişiklikler, https://avesis.medeniyet.edu.tr/dosya?id=44ce0733-cf95-48e1-9a3a-b0fd43805ebb 17/10/2022
- Ryan, J., Chaudieu, I., Ancelin, M. L., & Saffery, R. (2016). Biological underpinnings of trauma and post-traumatic stress disorder: Focusing on genetics and epigenetics. Epigenomics, 8(11), 1553–1569. https://doi.org/10.2217
- Yehuda, R., & Lehrner, A. (2018). Intergenerational transmission of trauma effects: putative role of epigenetic mechanisms. World Psychiatry, 17(3), 243–257. https://doi.org/10.1002/WPS.20568
- Jiang, S., Postovit, L., Cattaneo, A., Binder, E. B., & Aitchison, K. J. (2019). Epigenetic Modifications in Stress Response Genes Associated With Childhood Trauma. Frontiers in Psychiatry, 10, 808. https://doi.org/10.3389/FPSYT.2019.00808/BIBTEX
- O’Neill, L., Fraser, T., Kitchenham, A., & Mcdonald, V. (n.d.). Hidden Burdens: a Review of Intergenerational, Historical and Complex Trauma, Implications for Indigenous Families. https://doi.org/10.1007/s40653-016-0117-9
Figure References:
- Jiang, S., Postovit, L., Cattaneo, A., Binder, E. B., & Aitchison, K. J. (2019). Epigenetic Modifications in Stress Response Genes Associated With Childhood Trauma. Frontiers in Psychiatry, 10, 808. https://doi.org/10.3389/FPSYT.2019.00808/BIBTEX
- ACET GÖKÇE N.,2017, Travma Sonrası Stres Bozukluğunda Epigenetik Değişiklikler, https://avesis.medeniyet.edu.tr/dosya?id=44ce0733-cf95-48e1-9a3a-b0fd43805ebb 17/10/2022
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