Recent research published in molecular psychiatry There is evidence that experiencing abuse at various stages in childhood and adolescence changes how the brain processes emotions in adulthood. This study suggests that the particular age at which trauma occurs tends to determine which emotional processing areas of the brain become overactive later in life. These findings provide insight into why childhood maltreatment increases the risk of mental health disorders such as depression and post-traumatic stress disorder (PTSD).
The brain relies on a network of highly interconnected structures to interpret and respond to the social world. The two main regions involved in this neural network are the amygdala and the hippocampus. The amygdala acts as a center for rapid detection of emotional information, especially regarding potential environmental threats. The hippocampus works with the amygdala to provide context and link emotional responses to specific memories and past situations.
These brain regions help people process emotions at two completely different levels of consciousness. Conscious emotional processing occurs when a person has enough time to intentionally recognize and think about emotional triggers, and the brain’s higher thinking centers become involved. Non-conscious processing occurs in a fraction of a second, triggering automatic physical reactions before a person even realizes what they are looking at.
Mayuresh Kolgaonkar, associate professor and research director at the Center for Brain Dynamics at the University of Sydney’s Westmead Institute of Medical Research, wanted to investigate these developmental effects. He noted that the field needs a clearer understanding of these long-term emotional changes.
“Although it has long been known that childhood abuse increases the risk of mental health problems in adulthood, there is little understanding of how this adverse experience shapes the fundamentals of how we process and react emotionally,” Korgaonkar said. “We also don’t know when the brain is most vulnerable during development.”
Despite knowing that early trauma affects brain development, the scientific community lacks consensus on whether specific developmental windows are more sensitive to these perturbations. Past studies have often grouped childhood and adolescence together or used different definitions of childhood maltreatment. The authors designed this study to assess whether abuse experienced before the age of 13 has different effects on the brain than abuse experienced during adolescence.
“Although there has been a lot of interest in this topic, existing research is inconsistent, in part because it lumps together different ages and types of adversity,” Kolgaonkar explained. “We wanted to find out whether abuse before and after the age of 13, a key developmental milestone, leaves different imprints on how the adult brain processes emotions.”
He added that the research team chose this particular focus for practical clinical reasons. “We focused on emotional processing because difficulties in this area are among the most commonly reported problems in several mental health conditions,” Korgaonkar said.
The researchers also looked at a broad sample of people with a variety of mental health diagnoses. By including people with depression, anxiety, and PTSD alongside healthy adults, the scientists hoped to separate the specific effects of abuse from the effects of the mental health conditions themselves.
“Another important question is whether these effects are associated with a single disease or shared across diagnoses,” Kolgaonkar said. “And we tried to figure this out by recruiting cohorts with multiple mental illnesses in addition to healthy volunteers.”
To test these ideas, researchers analyzed data from 635 adult participants between the ages of 18 and 65. The sample included 399 adults with no history of abuse and 236 adults who reported experiencing emotional, physical, or sexual abuse before age 18. Participants were classified into diagnostic groups based on a structured psychiatric interview.
Participants underwent functional magnetic resonance imaging, commonly known as fMRI. This is a special type of brain scan that measures changes in blood flow to detect which areas of the brain are active in real time. While inside the scanner, participants completed a visual task that required them to view an image of a human face.
The images displayed six different facial expressions: fear, anger, sadness, disgust, happiness, and neutral expression. Faces were presented in two different ways to test different emotional pathways in the brain.
In the conscious processing task, faces were displayed on the screen for 500 milliseconds, which is long enough for people to clearly recognize emotions. In the non-conscious processing task, faces flashed on the screen for just 10 milliseconds, which is too fast to be consciously perceived.
The researchers then compared the brain activity of those who had experienced abuse and those who had not. They paid special attention to the age at which the trauma first occurred, dividing the abused group into those who experienced the trauma before the age of 13 and those who experienced it between the ages of 13 and 18. The data provide evidence that the timing of abuse clearly alters different neural pathways.
Korgaonkar pointed out that this particular split had unexpected consequences. “The most surprising thing was the ‘double dissociation’ that was separated by age,” he says.
“Those who were abused as teenagers showed increased activity in the amygdala, the brain’s rapid threat detector, but only during conscious emotional processing, when faces were shown long enough to be consciously recognized,” Korgaonkar told SciPost. “On the other hand, those who were abused before the age of 13 had increased activity in the hippocampus, an area that stores emotional memories, during rapid, sub-conscious processing of emotions and more automatic responses.”
This difference suggests that early childhood trauma may be hardwired into the brain as an automatic, non-conscious response to negative stimuli. Adolescent trauma, on the other hand, may particularly affect brain pathways involved in purposefully evaluating and thinking about emotional information.
“This means that the same type of adverse experience left its mark in different brain regions and in different processing modes, depending purely on the age at which it occurred,” Kolgaonkar said. “I think the main point is that it’s not just the fact of child abuse, but the timing of it that seems to be important.”
“People who were abused as children and those who were abused as teenagers showed different patterns of brain activity when processing facial emotions,” Korgaonkar added. “This suggests that adversity at different developmental stages leaves different imprints.”
The researchers also examined whether these brain changes were associated with specific psychiatric diagnoses or the severity of current symptoms. Increased hippocampal activity in the childhood maltreatment group appeared across all clinical diagnoses, suggesting that this is a systemic neural signature of early trauma.
“What’s important about our study is that these differences emerge across several mental illnesses and suggest persistent underlying characteristics, even after taking into account people’s current symptoms, rather than just a random reflection of how they’re feeling right now,” Korgaonkar said. This shows that early adversity does not just reflect temporary mood swings, but changes the underlying emotional hardware.
As with all research, there are some limitations. First, this data is based on participants retrospectively reporting their childhood experiences on a questionnaire. Retrospective recall may lack precision regarding the exact timing, nature, and severity of abuse.
“Readers should be aware that our study is a point-in-time snapshot that relies on adults recalling past abuse, which is less accurate than following people over many years,” Korgaonkar noted. “We also didn’t measure trauma in adulthood that may shape these neural signatures. We also focused on depression, anxiety, and stress disorders, so we can’t yet say how far these patterns extend to other conditions.”
Future research should utilize longitudinal designs that follow participants over many years from childhood to adulthood. By tracking individuals over long periods of time, scientists will be able to directly observe in real time how the brain changes after an adverse event. “An important next step is to measure in more detail when abuse occurs, ideally in studies that follow people over time rather than relying on recall, to see the effects of these timings,” Korgaonkar said.
The research team also plans to expand its focus to encompass a broader range of neural networks. “We also want to look beyond isolated brain regions and look at how emotional processing networks communicate across the brain (this is something we are currently working on) and explore whether these signatures can ultimately help us tailor treatment, help us know when to intervene and what kind of treatment to administer,” Korgaonkar explained.
Going forward, a better understanding of how the brain adapts to trauma at different ages could help medical professionals develop more targeted treatments for survivors of abuse. “Perhaps the most hopeful message is that understanding when and how adversity shapes the brain is a step toward more personalized care,” Korgaonkar concluded.
“It’s also worth emphasizing that these are group-level patterns,” Korgaonkar added. “These describe trends in many people and do not indicate a diagnosis or fate for individuals with a history of abuse.”
The study, “Scars of the Mind: Altered Limbic Brain Processing in Childhood Abused Adults in Mental Health Disorders,” was authored by Mayuresh S. Korgaonkar, Cheryl Tobler, Kim Felmingham, Leanne M. Williams, Richard A. Bryant, and Isabella A. Breukelaar.
