Investigation of structural changes in the brain of sexual trauma in female adolescents with sexual abuse

Introduction: Sexual abuse of children and adolescents is a public health problem that affects the whole society deeply, resulting in short and long term negative outcomes. Neuroplastic changes related to developmental processes, genetically programmed in puberty, occur during adolescence. It is known that the interruption of this developmental process and neuroplastic changes in the adolescent period due to sexual abuse prepares the ground for the changes in brain structure and functions, the connections between the brain circuits. In this study it was aimed to investigate the structural changes in the brain by comparing the brain imaging findings of resilient subjects who have been exposed to sexual abuse during adolescence and who had no psychological symptoms, vulnerable subjects who have been exposed to sexual abuse during adolescence and had psychiatric symptoms and adolescents who had no history of sexual abuse. Method: This study was carried out in a sample of 84 subjects aged between 14 and 18. Among those subjects there were a total of 30 sexually abused vulnerable patients who had psychiatric symptoms, 28 sexually abused resilient patients who had no psychiatric symptoms, 26 healthy controls who had no history of sexual abuse and who were at the same age, gender and socioeconomic level with resilient and vulnerable subjects. Two groups were separated, in order to distinguish resilient and vulnerable groups, based on the presence and absence of current psychiatric illnesses according to the clinician's semi-structured mental illness screening interview KSADS Affective Disorders and Schizophrenia Interview Schedule - Present and Lifetime version done by interviewing the adolescents and their parents. Connor Davidson psychological robustness scale was used in the determination of the adolescents to be included in the vulnerable and resilient groups at the second stage of the study. The socio-demographic data form, Beck Depression Scale, State Trait Anxiety Inventory Scale, Emotional Regulation Difficulties Scale, Coping Orientations to Problems Experienced Scale,Temperament Character Inventory, Childhood Trauma Scale, Social Support Perceived from Family and Friends Scale were performed to all subjects. WISC-R / WAIS-R intelligence tests 191 were applied to all subjects at Children's and Adolescent Psychiatry Department at Ege University. Structural Cranial Magnetic Resonance Imaging was performed using 3 tesla MRI instruments (Siemens Verio, Erlangen, Germany) in Ege University Radiology Department. Analyzes of MRI images were made with a Freesurfer (version 6.0) computer program. Cortical and subcortical structures were localized using Desikan atlas, followed by cortical thickness analysis with consideration of the number of vertices in the gray matter. These obtained ROIs (Region of Interest) values were then analyzed by the SPSS statistical program. Findings: The adolescents exposed to sexual abuse were younger than the control group. The depression and anxiety scores of the vulnerable group were higher than those of the resilient and control group. As expected, the Connor Davidson Resilience Scale showed a significant difference between the vulnerable group and the other groups. On the other hand, in the Childhood Trauma Scale, in which the severity of trauma was evaluated, the score of the vulnerable group was higher than the unaffected group. In all subscales and on the total score , the scores of the vulnerable group were higher than those of the resilient group. While the control group showed differences in all subscales and on the total score compared to vulnerable group; only the total score, emotional abuse and sexual abuse subscales differed with the resilient group. There was no difference between the control group and the resilient group in terms of the s Coping Orientations to Problems Experienced scores of the adverse events scale, whereas the vulnerable group showed a lower score than the other groups. When the intelligence levels of the adolescents were evaluated, the IQ levels in the vulnerable group were lower than those in the control group and the resilient group, whereas the mean IQ value of the resilient group was different from the control group. There was no difference in total intracranial volume between the groups. The only difference between the groups was determined as lateral orbitofrontal cortex (corrected with PF 0.034 FDR) , without any prediction for all areas. Thinning was detected in the left temporal cortex from as previously reported in other studies. This thinning was showed at superior and inferior temporal cortex in the affected group. Interestingly, the left hippocampal volume was larger in contrast to the expectation in the groups with trauma. In the right hemisphere, the cortex thickness was lower in the affected group than in the 192 control group. The affected group, had a thinner cortex especially around the central sulcus, when compared to resilient and the control group. Similarly, lateral orbitofrontal cortex and transverse temporal cortex were observed to be thinner in the affected group compared to the other groups. Insular thinning was different between only the affected group and control. In the regression analyzes performed to investigate the clinical parameters associated with cortical thinning, childhood trauma scale scores were found to be correlated with left inferior temporal and right orbitofrontal cortex. Resilience-related Connor-Davidson scale scores were associated with left superior temporal, right pre and paracentral cortex. One of two variables determining the thickness of the right hemisphere was Connor Davidson while the other was age. Conclusion: Our findings indicate that exposure to sexual abuse during adolescence has implications for brain development and neural plasticity. Key words: Adolescent sexual abuse, resilience, magnetic resonance imaging, cortical thickness, amygdala volume, hippocampal volume