Childhood Abuse Hit PTSD Symptoms Harder. Neglect Left a Bigger Mark on the Genes.

Ask most people to picture childhood trauma and abuse comes to mind before neglect does. A new genetic study of more than 144,000 people suggests that instinct might have the two backward, at least at the level of DNA.

Researchers at King's College London pooled genetic and mental health data from 144,702 adults across four UK studies: UK Biobank, the Genetic Links to Anxiety and Depression project, the Eating Disorders Genetic Initiative UK, and the COVID-19 Psychiatry and Neurological Genetics study. Every participant was assessed for PTSD symptoms and asked about eleven kinds of traumatic experience, five from childhood (emotional abuse, emotional neglect, physical abuse, physical neglect, and sexual abuse) and six from adulthood (serious accident, serious illness, sexual assault, violent crime, war exposure, and witnessing a death). The team then checked, at three genetic scales, whether some people's DNA made them react more strongly to specific kinds of trauma.

Abuse hit symptoms harder. Neglect cut deeper into the genes.

That split surprised the researchers as much as it will surprise most readers. Childhood abuse tracked more closely with how severe a person's PTSD symptoms were. Childhood neglect looked milder on that measure, yet its connection to a person's genetic risk was stronger, meaning genetics appeared to matter more for how neglect turned into symptoms than for how abuse did. Dr. Jonathan Coleman, the study's senior author, also co-leads King's College London's master's program in developmental psychology and psychopathology, and he ties the pattern to what is happening in a child's life at the time trauma hits.

“Childhood is a very important time. A lot of changes are happening both biologically, in terms of your brain maturing, and also socially, in the formation of relationships and personal identity. Disruption to that can have long lasting effects, and that might help us explain particularly strong relationships between genetic risk, childhood trauma and PTSD.”

A gene that only reacts to being ignored

FAM120A is involved in how the brain processes fear and stress, and in this dataset it interacted far more strongly with childhood emotional neglect than with abuse, accidents, assault, or any of the other nine trauma types. A separate gene, SGCD, showed one of the strongest trauma interactions in the entire analysis despite being linked mainly to muscle function, a result the researchers could not explain and flagged as an outlier rather than a finding.

“Broadly, this fits with the biology of PTSD being based in how the brain develops, how the cells of the brain communicate, and how the body responds to stress. When we looked across genes, we didn't identify any particular biological process that could explain why certain traumas seemed more strongly linked to genetics, so more research is needed.”

What the researchers still don't know

Coleman flagged a limitation in the design itself. Childhood, in this study, spanned less time than adulthood, and the five childhood categories covered a narrower range of experience than the six adult ones. Most PTSD genetics research to date has treated trauma as one category rather than splitting it by type and life stage, which is part of why this comparison had not been made at this scale before.

“Childhood is briefer than adulthood, and we examined a narrower set of experiences in childhood. These differences might make childhood look more important than it really is.”

None of this means a DNA test can tell someone whether a hard childhood will turn into PTSD. Coleman described a longer-term goal instead: using genetic screening alongside trauma history to flag people at higher risk earlier, so support arrives before symptoms harden into a diagnosis. For now, the finding that stands is narrower and stranger than any screening tool. The trauma that hurt less on paper, neglect, left the deeper mark in the genes.