Unique neural signatures of childhood sexual abuse revisited

Childhood sexual abuse (CSA) constitutes a detrimental subtype of childhood maltreatment (CM) associated with high trauma load and adverse health outcomes. Previous studies indicate CSA-specific reductions in gray matter volume (GMV) and cortical thickness. It remains challenging to disentangle brain alterations associated with CSA from those related to trauma intensity or psychopathology. Here, we apply a novel approach, comparing individuals with CSA, non-sexual maltreatment, and a non-maltreated control group, to identify CSA-specific findings. Drawing from a cohort of n=2039 depressed and healthy men and women allowed us to match groups 1:1 for age, sex, depression diagnosis, and, for maltreated groups, trauma load. The Childhood Trauma Questionnaire was used to assess childhood maltreatment. Applying threshold-free cluster enhancement, we investigated GMV and cortical thickness in n=195 adults with CSA compared to non-sexually maltreated (nCSA, n=195) and non-maltreated (nCM, n=195) individuals. CSA showed larger GMV in the right cerebellum compared to nCSA but not compared to nCM. CSA displayed larger cortical thickness encompassing the bilateral superior frontal gyri, pre- and postcentral gyri, supramarginal gyri, superior parietal cortices, precunei, and insulae, compared to both nCSA and nCM. This is the largest study to investigate CSA-specific effects on brain morphometry, applying matched group comparisons. These findings highlight distinct neural signatures of CSA, characterized by preserved cortical thickness in regions also affected by major depression, and larger cerebellar GMV compared to non-sexual types of maltreatment. These results underscore the importance of distinguishing between types of childhood maltreatment and considering confounding factors when assessing their neurobiological impacts.