Morphometric alterations related to emotion dysregulation, anxiety and self-harm in adolescents with borderline personality disorder A Source-based morphometry study

Objective. Difficulties in emotion regulation are common features of borderline personality disorder in adolescents (aBPD). Previous research suggests that adolescents with BPD exhibit distinct neuroanatomical alterations, although methodological limitations such as low sample size, and the reliance on univariate massive statistical analyses, prevent conclusions. Moreover, the possibility to predict new cases was not tested. This study aims to examine structural brain differences using an unsupervised machine learning method known as Source-Based Morphometry (SBM), to the largest sample to date of aBPD. We hypothesize that adolescents with BPD will exhibit increased gray matter volume in the default mode network (DMN) and cerebellum, strictly related with emotion dysregulation and borderline symptoms, alongside reduced gray matter in frontal control networks. Methods. High-resolution T1-weighted structural MRI of 129 adolescents with BPD (aged 12–17) and 107 age-, gender- and education-matched healthy controls (HCs) were analyzed using SBM to identify networks of covarying gray matter concentration (GMC). Borderline symptomatology, difficulties in emotion regulation, anxiety related problems, and global functioning were assessed to characterize the meaning of neural findings. Results. Compared to HCs, adolescents with BPD exhibited significant increased GMC in regions overlapping with the posterior hub of the DMN, and the cerebellum, and reduced GMC in frontal control regions. Importantly the GMC alterations inside the cerebellum and the DMN positively correlated with the difficulties in emotion regulation such as emotional clarity and emotion regulation difficulties, self-harm injuries, anxiety and depressive symptoms, and negatively correlated with global assessment functioning. Conclusions. Our findings suggest that gray matter alterations in regions ascribed to default mode network, cerebellum, and frontal control regions play a crucial role in adolescent BPD. These structural changes may underlie deficits in emotional regulation and self-injurious behaviors, providing new insights into the neurobiological mechanisms of BPD in youth and pave the way for neurostimulation treatments.