How Does Intergenerational Trauma Work?

Intergenerational trauma is the theory that trauma can be inherited because there are genetic changes in a person’s DNA. The changes from trauma do not damage the gene (genetic change). Instead, they alter how the gene functions (epigenetic change).

Epigenetics is the study of the effects that environment and behavior have on genes. For example, in 2008, researchers found an association between prenatal exposure to famine and an offspring’s later adult disease risk. The offspring in the study had less DNA methylation (a biological process that controls how genes are expressed) of the imprinted IGF2 gene.2 Additional studies have supported the idea that an ancestor’s exposure to trauma may impact future generations.

Even so, the science of epigenetics is still in its infancy. Further research is needed to definitively say whether a parent's—or even grandparent’s—trauma can be passed down generationally. Here is an overview of what is known about the theory of intergenerational trauma.

What Is Intergenerational Trauma?

Trauma is a person's emotional response to a tragic event (for example, accidents, sexual violence, and natural disasters). Long-term trauma is marked by having flashbacks, unpredictable emotions, and physical symptoms like nausea and headaches.3

While epigenetic studies have found correlations between prenatal and preconception trauma and gene methylation in offspring, not all scientists agree with the findings.

Criticism

A 2015 study on Holocaust exposure and intergenerational effects found an association between preconception trauma and epigenetic alterations in the parent and the offspring.4 However, the study was criticized because of its small sample size and because the researchers studied blood and a small subset of genes.

A more general criticism is that social epigeneticists make far-reaching claims by focusing on epigenetics in biology and ignoring established facts about genetics and cell biology.

Epigenetics and Trauma Research

The field of epigenetics is focused on how behaviors and the environment influence the way your genes work.1 Genetic changes affect which proteins are made, and epigenetic changes affect a gene’s expression to turn genes on or off.

There have been multiple observational studies on how experiencing a famine prenatally affects offspring. The researchers found a consistent correlation between prenatal exposure to famine and adult body mass index (BMI), diabetes, and schizophrenia.6

Another study in 2018 found that the male offspring of Civil War soldiers who spent time as prisoners of war (POWs) were more likely to die early after age 45 than people whose fathers had not been POWs. The researchers concluded that paternal stress could affect future generations and that the impact may occur through epigenetic channels.7

Long-Term Effects

It's known that trauma can influence a person’s psychological, emotional, and physical health for a lifetime. If trauma can be passed down epigenetically, it would make sense that it could have the potential to affect future generations’ lives as well.8

The potential long-term effects of trauma include:

• Emotional dysregulation
• Numbing or detachment from thoughts, behaviors, and memories
• Sleep disturbances
• Substance use disorders
• Physical symptoms, such as gastrointestinal, cardiovascular, neurological, musculoskeletal, respiratory, and dermatological symptoms
• Hyperarousal/hypervigilance
• Intrusive thoughts and memories
• Triggers and flashbacks
• Disassociation, depersonalization, and derealization
• Self-harm

Acute stress disorder is a normal stress response that usually resolves within four weeks. In that time, a person may have symptoms such as feeling overwhelmed, needing to talk about the trauma they experienced, hypervigilance, and avoidance.

Post-Traumatic Stress Disorder

Post-traumatic stress disorder (PTSD) is a mental health condition that develops after trauma. In this case, a person's symptoms last longer than four weeks and span several categories.8

To be diagnosed with PTSD, a person must have nine out of 14 symptoms within the following categories:

• Intrusion
• Negative mood
• Disassociation
• Avoidance
• Arousal

Coping and Treatment

Treatment options for PTSD include medication and psychotherapy. Each person with the condition will respond differently to different treatments.

It's important to find a mental health provider who is experienced with PTSD and understands the various treatment modalities—especially if there are coexisting disorders like panic disorder, depression, substance use disorder, and suicidal ideation.11

Antidepressants are the most commonly used medication to treat PTSD. These medications can help with symptoms like sadness, anxiety, anger, and numbness.11 However, if your symptoms include sleep disturbances and nightmares, your doctor may consider other medications to help address those needs.

Psychotherapy for PTSD focuses on identifying symptoms and triggers, as well as learning skills to manage them. Cognitive behavioral therapy (CBT) is one therapy used for PTSD.11 CBT employs different strategies, including:

• Exposure therapy: Gradually exposing people to the trauma they experienced in a safe way to help them learn how to face and control their fear
• Cognitive restructuring: Helps people make sense of their traumatic memories

People who face stigma and discrimination are more vulnerable to PTSD. Therefore, treatment for trauma needs to be tailored to a person’s culture and beliefs. Providers need to be informed about how factors like race, immigration status, housing insecurity, poverty, gender identity, sexual orientation, and age influence ongoing trauma.12

A Word From Verywell

Intergenerational trauma may exist, but epigenetic science is still young. What is known is that some people are more biologically susceptible to PTSD, that PTSD is prevalent, and that epigenetic changes can be reversed. Together, these factors highlight why more research into intergenerational trauma is needed.

It's vital to identify and treat trauma—whether it's generational or not. While medication and psychotherapy are proven therapies for PTSD, individuals respond to treatments differently.

It's also essential that clinicians—especially those who work with marginalized communities—are culturally competent and able to consider how discrimination and inequality contribute to ongoing trauma.

If you have experienced trauma, look for mental health providers who are experienced with PTSD and who can modify treatment plans to fit your needs.

Frequently Asked Questions

What are examples of intergenerational trauma? 

Researchers have studied several historical cases in which trauma was widespread in populations when people experienced traumatic events like famines, war, and genocide.

How is trauma passed down?

Intergenerational trauma is believed to pass from one generation to the next through genetic changes to a person’s DNA after they experience trauma. There is some evidence that these genetic markers are passed on to a person's offspring.

Is PTSD hereditary? 

Genetics may make some people more biologically susceptible to PTSD.13 In addition, epigenetics research points to a correlation between parental trauma and changes in an offspring’s DNA.

The field of epigenetics is still young. More research is needed and is important because epigenetic changes are reversible.