Borderline Personality Disorder With Cocaine Dependence: Impulsivity, Emotional Dysregulation and Amygdala Functional Connectivity

Abstract

Background: Borderline personality disorder is present in 19% of cocaine dependence cases; however, this dual pathology is poorly understood. We wished to characterize the dual pathology and find its functional connectivity correlates to better understand it. Methods: We recruited 69 participants divided into 4 groups: dual pathology (n = 20), cocaine dependence without borderline personality disorder (n = 19), borderline personality without cocaine dependence (n = 10) and healthy controls (n = 20). We used self-reported instruments to measure impulsivity and emotional dysregulation. We acquired resting state fMRI and performed seed-based analyses of the functional connectivity of bilateral amygdala. Results: Borderline personality disorder and cocaine dependence as factors had opposing effects in impulsivity and emotional dysregulation, as well as on functional connectivity between left amygdala and medial prefrontal cortex. On the other hand, in the functional connectivity between right amygdala and left insula, the effect of having both disorders was instead additive, reducing functional connectivity strength. The significant functional connectivity clusters were correlated with impulsivity and emotional dysregulation. Conclusions: In this study, we found that clinical scores of dual pathology patients were closer to those of borderline personality disorder without cocaine dependence than to those of cocaine dependence without borderline personality disorder, while amygdala-medial prefrontal cortex functional connectivity patterns in dual pathology patients were closer to healthy controls than expected.

Keywords: amygdala; borderline personality disorder; cocaine dependence; dual pathology; functional connectivity; neuroimaging.

Figure 1

(A–D) Score from the total and subscales from the BIS-11. p value was corrected for multiple comparisons to < 0.01. Note: ^*p < 0.05, ^**p < 0.01, ^***p < 0.001. BIS-11, Barratt Impulsiveness Scale; BPD, borderline personality disorder; CD, cocaine dependence.

Figure 2

Results from the DERS. (A) At total scores, besides the difference between each clinical group and the BPD−CD− group, the difference is near significance between the BPD-CD+ and the BPD+CD+ groups, and the former with the BPD+CD−. (B–C) show graphs with a similar shape than (A), but without the significant results. (D) There were no differences between groups in awareness subscale. (E) For clarity subscale only CD groups differed from BPD-CD-. (F) Negative significant interaction from the ANOVA at goals subscale (F = 6.19, p = 0.05) and in the borderline personality disorder factor (F = 34.84, p < 0.001). When adding cigarettes/day as covariate, the R² improves to 0.421, remaining the interaction significant (F = 5.33, p < 0.05) and the BPD factor (F = 32.04, p < 0.001), but not the covariate. On (A–C) p-value corrected for multiple comparisons to < 0.01. ^*p < 0.05, ^**p < 0.01, ^***p < 0.001. DERS, Difficulties in Emotion Regulation Scale; BPD, borderline personality disorder; CD, Cocaine dependence.

Figure 3

Amygdala connectivity. (A–C) Show the significant clusters from lAmy-mPFC connectivity analysis: (A) the CD effect, (B) the BPD effect and (C) the interaction. (D) Left and right amygdala seeds. (E) resting state functional connectivity effect sizes for each group with 95% confidence intervals (error bars). lAmy, left amygdala; mPFC, medial prefrontal cortex; CD, cocaine dependence; BPD, borderline personality disorder.

Figure 4

Functional connectivity between rAmy-lIns. (A) Clusters 1 (green) and 3 (red), (B) Cluster 2, (C) media correlation of each group with a confidence interval at 95%. Note: rAmy, right amygdala; lIns, left insula; BPD, borderline personality disorder; CD, cocaine dependence.

Figure 5

Associations between amygdala functional connectivity and impulsivity. (A) lAmy-mPFC connectivity from cluster resulted from the BPD × CD interaction with total BIS-11 score correlation (B) rAmy-lIns connectivity from cluster 1 resulted from the BPD × CD interaction with non-planned BIS-11 score correlation. l/rAmy, left/right amygdala; mPFC, medial prefrontal cortex; BPD, borderline personality disorder; CD, cocaine dependence; BIS-11, Barratt Impulsiveness Scale.