BACKGROUND: The understanding of the neural correlates of borderline personality disorder (BPD) is limited, but suggests alterations in limbic structures play a role in adult BPD. The developmental course of structural neural differences in BPD is unknown. Whether there is specificity for structural alterations in BPD compared with other psychiatric presentations, such as major depressive disorder (MDD), remains unexplored. The current study examined childhood trajectories of two limbic regions implicated in BPD, hippocampal and amygdala volume, as they relate to adolescent BPD symptoms as compared with MDD symptoms. METHODS: Participants (N =175
85 [48.6%] female) were from a 17-year longitudinal study of preschool depression. Participants completed up to 5 MRI scans from late childhood through adolescence. General linear models assessed the relationship between gray matter volume intercepts/slopes and BPD symptoms to understand the influence of the developmental trajectory of brain regions on BPD. Separate models assessed the relationship between MDD symptoms and volume intercepts to assess diagnostic specificity. RESULTS: Lower childhood amygdala volume (intercept
age 13 centered) across scans was associated with higher adolescent BPD symptoms (β=-0.25, adj. p=.015). There was no relationship between the slope of amygdala volume and BPD symptoms. There was no relationship between hippocampal volume and BPD, nor any relationship between amygdala or hippocampal volume and MDD symptoms in adolescence. CONCLUSIONS: Our findings add evidence for the role of alterations in amygdala structure in BPD development. Decreased amygdala volume as early as age 13 may be an early indicator for the development of BPD in adolescence.