Adults Who Were Sexually Abused As Children Have Lower Gray Matter Volume In A Specific Region Of The Brain, Study Finds

A study in South Korea found that people who survived childhood sexual abuse and who currently suffer from major depressive disorder had significantly lower gray matter volume in the right middle occipital gyrus region of the brain. . Their gray matter volume in this specific region was lower than that of healthy adults and people with depression who were not sexually abused in childhood. The study was published in Psychiatric research.

Childhood maltreatment has been shown to be associated with a number of negative outcomes in adulthood. These include negative self-perceptions, easy loss of temper, verbal aggression, drug and alcohol abuse, sexual misconduct, and many other issues. .

Research has shown that childhood abuse also makes a person more vulnerable to a wide range of psychiatric disorders, including major depressive disorder (depression), post-traumatic stress disorder, borderline personality disorder, and panic disorders. Depending on the type of abuse suffered, researchers have found between 1.5 and more than 3 times greater risk of depression in people who were abused as children.

However, the neurobiological mechanisms responsible for this increased vulnerability are currently unknown. Existing studies have linked depression to reduced gray matter volume in the brain, but few studies have focused on structural brain abnormalities related to childhood maltreatment.

Study author Soo Young Kim and her colleagues hypothesized that different types of childhood abuse would also be associated with decreased gray matter volume in the brain, whether or not the person has depression. They also expected that even in patients with depression, a history of a specific type of childhood abuse would be associated with decreased gray matter volume.

For their study, the researchers recruited 75 people with depression and 97 healthy participants. This took place between May 2019 and February 2021. All participants with depression were patients at the psychiatric outpatient clinic at Korea Anam University Hospital in Seoul. Healthy participants were recruited using advertisements from the local community. All participants were right-handed. The average age of the participants was around 37 years old.

Participants in both groups completed ratings of the severity of depressive symptoms and childhood trauma. The Childhood Trauma Assessment assessed three types of abuse (sexual, physical, and emotional) as well as physical and emotional neglect. In this study, the researchers focused on the three types of abuse. Based on the results of this assessment, participants were then divided into ‘childhood abuse’ and ‘non-abused’ groups. Participants also underwent magnetic resonance imaging.

The results showed that participants with depression had lower gray matter volume in the anterior cingulate gyrus, left short insular gyrus, and right pars triangularis regions of the brain compared to healthy participants.

Participants who experienced childhood sexual abuse showed significantly smaller cortical gray matter volume in the right middle occipital gyrus, right pars orbitalis, left superior parietal lobule, and left pars triangularis regions of the brain. compared to participants who did not experience childhood sexual abuse (in the total sample). No cortical region of participants who experienced childhood sexual abuse had higher gray matter volumes than participants who were not abused.

The results also showed that higher scores on the Childhood Sexual Abuse Assessment were linked to smaller sizes in the middle occipital gyrus region of the brain. This association was not present in survivors of other types of abuse.

“Our results suggest that exposure to childhood sexual abuse is related to a significant decrease in the cortical volume of the right middle occipital gyrus – which corresponds to a visual cortex – in a group of adult patients with major depressive disorder and healthy participants,” study authors wrote. “We also compared patients who experienced physical or emotional abuse in childhood with those who did not; however, no significant differences were found in cortical volumes.

“Additionally, we observed reduced volume in the right anterior cingulate gyrus in patients with major depressive disorder compared to that in healthy participants,” they continued. “While childhood sexual abuse and major depressive disorder affected the cortical volume of the right middle occipital gyrus and anterior cingulate gyrus, respectively, post-hoc analyzes showed that even patients in the major depressive disorder group who been exposed to sexual abuse in childhood showed a decrease in volume of the right middle occipital gyrus.

The study contributes to knowledge of the neurobiological underpinnings of the relationships between negative childhood experiences and later outcomes. However, it also has limitations that must be taken into account. Notably, in some comparisons, the groups of participants were too small for the differences in observed size to be detectable using the applied statistical procedures. In addition, the study design does not allow for causal conclusions to be drawn about the observed associations.

The study, “Child abuse and cortical gray matter volume in patients with major depressive disorder,” was authored by Soo Young Kim, Seong Joon An, Jong Hee Han, Youbin Kang, Eun Bit Bae, WooSuk Tae, Byung-Joo Ham and Kyu-Man Han.

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