Examining the common and specific grey matter abnormalities in childhood maltreatment and peer victimisation

Abstract

Background: Early-life interpersonal stress, particularly childhood maltreatment, is associated with neurobiological abnormalities. However, few studies have investigated the neural effects of peer victimisation.

Aims: This study examines common and specific associations between childhood maltreatment, peer victimisation and brain structural alterations in youths.

Method: Grey matter volume (GMV) and cortical thickness data were collected from 105 age- and gender-matched youths (age range: 17-21 years). Region-of-interest and whole-brain analyses were conducted.

Results: For the region-of-interest analyses, the childhood maltreatment group had smaller GMV than controls in left inferior frontal gyrus, bilateral anterior insula, postcentral and lingual regions, which were associated with greater emotional abuse, along with smaller insular GMV than the peer victimisation group, who had smaller left lingual and postcentral GMV than controls. At the whole-brain level, both childhood maltreatment and peer victimisation groups had smaller GMV than controls in a cluster comprising left post/precentral, inferior frontal gyrus, insula, superior parietal and supramarginal gyri. The peer victimisation group alone had increased cortical thickness in a cluster comprising left superior frontal, anterior cingulate and medial orbitofrontal gyri, which was related to greater cyberbullying.

Conclusions: Early-life interpersonal stress is associated with common structural alterations of the inferior frontal-limbic, sensory and lingual regions involved in cognitive control, emotion and sensory processing. The findings of childhood-maltreatment-related reduced anterior insular GMV and peer-victimisation-related increased cortical thickness in the left medial prefrontal-anterior cingulate cluster underscore the distinctive negative effects of childhood maltreatment and peer victimisation, and suggest that peer victimisation, particularly cyberbullying, could be as detrimental as childhood maltreatment.

Keywords: Childhood experience; imaging; neuroanatomy; social deprivation; trauma.

Fig. 1

Axial sections of grey matter volume reduction in the childhood maltreatment group compared with the control group (shown in red), as revealed by F-test (P < 0.05), family-wise error-corrected at the cluster level. The cluster was also significantly reduced in the peer victimisation group relative to the control group only. Axial slices are marked with the z-coordinate as distance in millimetres from the anterior–posterior commissure. The right side of the image corresponds to the right side of the brain.

Fig. 2

Significant vertex-wise cortical thickness cluster superimposed on a template reconstruction of brain surface in Montreal Neurological Institute (MNI) space. The significant cluster shows reduced cortical thickness in the childhood maltreatment group compared with the peer victimisation group, as revealed by F-test (P < 0.05), family-wise error-corrected. The cluster was also significantly reduced in the control group relative to the peer victimisation group only. The colour bar represents T statistics.

Fig. 3

Significant gene×environment interaction effects between group (childhood stress exposed versus unexposed controls) and MAOA genotype on grey matter volume of (a) left hippocampus and (b) right hippocampus, P < 0.05. GMV, grey matter volume; MAOA, monoamine oxidase type A.