Is PTSD hereditary? How genes play a role

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Some medical conditions, such as Down syndrome, are purely hereditary. This means that if a person has the specific genetic change associated with the condition, they will develop it.

PTSD is not hereditary in this sense. Researchers have not identified a single gene or combination of genes that inevitably cause PTSD or explain all cases.

Additionally, while scientists have identified some genes that may elevate the risk of developing PTSD, a person cannot develop the condition without experiencing something traumatic. Experiences of trauma are the primary cause of PTSD.

Research findings

Among those who experience traumatic events, PTSD appears to have relatively low heritability. This means genes have a small influence on who develops the condition.

A 2019 meta-analysis found that genetics accounted for 5% to 20% of the cases the authors analyzed, depending on other variables.

Other mental health conditions have higher rates of heritability.

For example, according to a 2019 review, the heritability estimate for schizophrenia is 60% or higher, while major depression has a heritability estimate of 35%.

To receive a diagnosis of PTSD, a person must have experienced an event that they perceive as threatening. This could involve:

• a single event that affected them directly, such as an assault
• a series of events or an ongoing experience, such as discrimination or an abusive relationship
• witnessing or hearing about an experience that happened to someone else, such as a loved one

For this reason, a person’s environment is highly influential in the development of PTSD. However, not everyone who experiences trauma will develop the condition.

Factors other than the environment may explain why people respond differently to traumatic situations. Genetics may be one of these factors, potentially accounting for a small portion of the differences in individuals who experience trauma.

Research is also beginning to suggest that exposure to trauma can alter a person’s genes and may influence gene expression or behavior.

Learn more about the causes of PTSD.

PTSD can run in families, but this is not due only to genetics. While parents may pass on genes that elevate the risk of developing PTSD, the condition can only occur in response to trauma.

There are many ways that traumatic events or situations could affect multiple generations of a family, including:

• Exposure to environmental factors: Multiple generations of a family may experience the same traumatic events due to their environment. These include income inequality and discrimination.
• Parental mental health: A parent or caregiver having PTSD may be traumatizing for a child. They may feel confused or scared by the symptoms and not understand their caregiver’s behavior. Learning about a caregiver’s experiences may also be traumatic.
• Parenting approach: A 2018 study found an association between PTSD and certain parenting practices, such as controlling or hostile behavior. The study did not establish that PTSD directly causes these practices, though. More research is necessary.
• Abuse: A 2022 study found an association between PTSD symptoms and more positive views of corporal punishment. This was especially true for people who had experienced childhood sexual assault. It is unclear why this connection may exist or whether PTSD itself is responsible for the views.
• Substance misuse: Some people with PTSD may engage in alcohol or drug misuse to try to manage their symptoms. These or other behaviors may create an unsafe environment for a child.

It is important to note that these behaviors are not necessarily intentional. Many parents and caregivers do not mean to cause a child to experience trauma and may try very hard to avoid it.

Other risk factors for PTSD include:

• past experience of traumatic events, particularly in childhood
• a lack of social support after the event
• having a personal or family history of mental health conditions
• having a personal or family history of substance misuse

PTSD is twice as common in females as it is in males. This may be because females are more likely to experience the types of traumatic events that often lead to PTSD.

For example, females experience sexual assault more often than males. Up to half of females who have been raped develop PTSD.

People can also develop PTSD as a result of direct and institutional racism. Additionally, research suggests racial bias may affect rates of PTSD diagnosis among certain groups.

Learn more about racial trauma and PTSD in women.

The most straightforward way to reduce the effects of PTSD is to seek help and treatment. Several behaviors may also reduce the risk of developing PTSD or help people manage its effects, such as:

• seeking social support where possible
• making attempts to cope with the event in active ways
• using grounding techniques or learning mindfulness
• strengthening self-esteem

Within families

People may be able to introduce the techniques above to family members. For example, they may help children develop self-esteem and feelings of competence or teach them about managing strong emotions.

Whether a person tells children in their care about their traumatic experiences is a personal choice. For those who want to, researchers have differing opinions on how best to do this.

While complete secrecy and silence may be unhelpful, disclosing everything may also be distressing for all parties. Instead, it may help to consider what the child needs to know to meet their emotional needs at their current age or in their current situation.

If a child discloses traumatic experiences to a caregiver, it is best to let the child speak about the trauma whenever they need to, without pressuring them to do so.

Help is available for people who are concerned they or their child may have PTSD. They can discuss support and treatment options with a doctor or mental health professional.

It may be challenging for people who do not have a significant amount of disposable income to access this form of treatment. However, trauma therapists may offer reduced rates, and several support organizations provide free PTSD resources.

Learn more about free and low cost online therapy.

Post-traumatic stress disorder (PTSD) is not a genetic disorder in the traditional sense, but it can run in families. This is generally primarily due to environmental factors, but genetics can play a role, too.

Some genes may increase a person’s risk of developing PTSD if they experience trauma, but the condition cannot develop on its own. The events and environmental factors that cause PTSD can occur in cycles that affect multiple generations.

PTSD is treatable, and support is available to reduce the symptoms and help with related issues in family relationships. If a person thinks they or a child in their care may have PTSD, it is best they seek help from a doctor or mental health professional.