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Post-traumatic stress disorder (PTSD) is a mental illness that can occur after exposure to extremely traumatic events, such as military combat or violent attacks. This is the only mental disorder that requires an external event for a positive diagnosis. Symptoms of PTSD include:
- Intrusive, uncontrollable memories of the event
- Avoid places and things that remind us of what happened
- Increased irritability, agitation, and negative thoughts about oneself
These symptoms can be so severe that they interfere with normal function, such as work, school, or family interactions. The prevalence of violence in major cities indicates that many people will be exposed to traumatic events; However, only a small percentage of those who survive trauma will develop PTSD. Estimates of the prevalence of PTSD in the general population are around 10%, meaning that 90% of people who experience terrifying situations will recover from their initial stress reactions. This statistic alone suggests that some people are more vulnerable, and others are more resilient to shocks.
Grady Trauma Project
There are many factors that contribute to this vulnerability, but genetics appears to be one way in which some people are biologically more predisposed to developing PTSD. In this way, PTSD provides the ideal context for studying nature (genes) versus nurture (extreme environmental influence) in mental illness. Twin studies have long shown that PTSD is genetic, however, identifying specific genetic patterns of risk has been difficult because such research requires DNA from a large number of people.
Our recent studies in the Grady Trauma Project, where we interviewed and collected saliva samples from thousands of people in downtown Atlanta, have pointed to several potential genetic markers of risk. Two of these genes, FKBP5 and ADCYAP1R1 is involved in the hormonal stress response and is linked to changes in the brain that regulate feelings of fear. Polymorphism (i.e. mutation) in FKBP5 The gene is associated with either risk or resilience in PTSD.
Specifically, individuals with the resilient genotype do not show increased symptoms of PTSD even if they have experienced multiple instances of child abuse. Polymorphism in the second gene ADSIAP1R1, It seems to increase the risk in women but not men. This particular gene responds to the levels of the female estrogen cycle, such that women are more likely to develop PTSD between puberty and menopause. Research has shown that women are twice as likely to develop PTSD than men. At least part of this discrepancy comes from female biology.
Redirect treatments and address environmental factors
Understanding the genetic and biological basis of frailty will enable improved medical procedures in the future; Ideally, individuals with different genetic polymorphisms would receive a different, more targeted treatment. However, it is important to remember that an individual’s genotype does not solely determine his or her fate. While a single gene cannot determine whether someone will develop PTSD, mutated genes can indicate increased risk.
In addition, there are many factors that can counteract this genetic risk and protect the individual from its effects even in the event of trauma. One such factor is having a supportive social network in the aftermath of trauma. Having friends and family available to provide emotional and physical support goes a long way in mitigating the effects of a traumatic experience. Another resilience factor is optimism and humor. Although it is difficult to see the silver lining after a horrific experience, if a person is able to find and appreciate it, they are less likely to develop PTSD, even if they were born with risk genes.
