By Ilona Phillips, LMSW, founder of Lotus Consulting in Ann Arbor, Michigan
A new study from King’s College London offers a more useful question than whether PTSD is caused by genes or by trauma. It asks whether genetic vulnerability may matter differently depending on the kind of trauma a person has lived through. That is closer to how trauma actually works. No one arrives at a difficult experience as a blank slate, and no gene operates outside a life.
What the study found
The researchers analyzed genetic and mental-health data from 144,702 people in UK cohorts. Participants reported exposure to eleven potentially traumatic experiences, including childhood emotional and physical neglect, childhood abuse, serious illness, sexual assault, violent crime, war exposure, and witnessing death. The researchers then examined PTSD symptoms alongside polygenic risk scores, particular genes, and specific genetic variants.
On average, childhood traumas showed stronger associations with PTSD symptoms and stronger gene-environment interactions than adult traumas. The clearest interactions appeared around childhood emotional and physical neglect. In plain language, inherited differences appeared to matter more to variation in PTSD symptoms among people who had experienced those forms of childhood trauma than they did across many of the adult trauma categories.
That does not mean a child with a particular genetic profile is destined to develop PTSD. It also does not mean childhood trauma somehow changes a person’s DNA sequence, or that adult trauma is less serious. The study measured self-reported trauma and PTSD symptoms in UK adults. It cannot tell us why the childhood findings were stronger, how any one person will fare, or which single gene determines an outcome.
Why neglect deserves particular attention
Emotional and physical neglect are often discussed as though they are individual events. They are more commonly part of a developmental environment: protection is unreliable, comfort may be absent, adults may be overwhelmed or unavailable, and a child has few ways to leave, seek care, or make sense of what is happening. That is part of what clinicians mean by complex trauma.
The study did not prove that this ongoing context explains its findings. It is, however, a clinically important possibility. A child is still developing ways to regulate fear, ask for help, trust other people, and recover after distress. When the people who should provide safety are themselves inconsistent, impaired, frightening, or unavailable, the trauma is not simply something that happened in the past. It can organize the child’s daily world.
This is also where genetic and environmental explanations become difficult to pull apart. Caregivers’ trauma histories, mental and physical health, substance use, access to support, and inherited vulnerabilities can affect both a child’s environment and the child’s own risk profile. That does not excuse neglect or make it inevitable. It means that a responsible account of childhood trauma has to look at the whole system rather than locating the cause in one child’s biology.
What about epigenetics
People often hear a study like this and assume it means trauma has changed someone’s genes. That is not what this research examined. The study looked at inherited genetic variation and how it interacted with different reported trauma exposures. Epigenetics is a related but distinct field that studies processes that can influence how genes are expressed without changing the underlying DNA sequence. There is active research on trauma and epigenetic processes, but this particular study cannot be used as evidence that childhood trauma altered participants’ genes.
Why adult trauma is not a lesser category
The contrast in this study should not be turned into a hierarchy of suffering. Adults can develop severe, enduring PTSD after assault, combat, violence, catastrophic illness, loss, or prolonged coercion. Some adult trauma is acute; some unfolds over years. Adults may sometimes have a wider range of coping skills, relationships, practical resources, or access to treatment than children do, but those supports are unevenly distributed and can disappear under extreme stress.
The more careful takeaway is that the timing and type of trauma may change how genetic vulnerability shows up. A person’s response is also shaped by what happened next: whether anyone believed them, whether they were protected, whether the danger ended, what meaning they made of the experience, and whether they had support while trying to recover.
What this means in therapy
Genetic research can be useful when it makes us less simplistic. It should not give anyone a new identity as permanently damaged or biologically doomed. In therapy, the practical work remains recognizably human: understanding how a person learned to manage threat, identifying what still triggers the nervous system, building skills for emotion regulation and relationships, and creating conditions in which safety and choice become more available.
A good trauma formulation holds both truths. Biology matters. So does the environment that shaped a person, the supports they did or did not receive, and the possibilities that remain open now.
Source
Knyspela, J., et al. (2026). Identifying differential interactions of potentially traumatic experiences with genetic risk for posttraumatic stress disorder. European Journal of Psychotraumatology, 17(1), 2709319. https://doi.org/10.1080/20008066.2026.2709319
