Supplementary Material for: Hippocampal dynamic functional connectivity, HPA axis activity, and personality trait in bipolar disorder with suicidal attempt

Introduction Suicide in bipolar disorder (BD) is a multifaceted behavior, involving specific neuroendocrine and psychological mechanisms. According to previous studies, we hypothesized that suicidal BD patients may exhibit impaired dynamic functional connectivity (dFC) variability of hippocampal subregions and hypothalamic-pituitary-adrenal (HPA) axis activity, which may be associate with suicide-related personality traits. The objective of our study was to clarify this. Methods Resting-state functional magnetic resonance imaging data were obtained from 79 patients with BD, 39 with suicidal attempt (SA) and 40 without SA, and 35 healthy controls. The activity of the HPA axis was assessed by measuring morning plasma adrenocorticotropic hormone (ACTH) and cortisol (CORT) levels. All participants underwent personality assessment using Minnesota Multiphasic Personality Inventory-2 (MMPI-2). Results BD patients with SA exhibited increased dFC variability between the right caudal hippocampus and the left superior temporal gyrus (STG) when compared with non-SA BD patients and HCs. BD with SA also showed significantly lower ACTH levels in comparison with HCs, which was positively correlated with increased dFC variability between the right caudal hippocampus and the left STG. BD with SA had significantly higher scores of Hypochondriasis, Depression and Schizophrenia than non-SA BD. Additionally, multivariable regression analysis revealed the interaction of ACTH × dFC variability between the right caudal hippocampus and the left STG independently predicted MMPI-2 score (depression evaluation) in suicidal BD patients. Conclusion These results suggested that suicidal BD exhibited increased dFC variability of hippocampal-temporal cortex and less HPA axis hyperactivity, which may affect their personality traits.

引言 双相情感障碍（bipolar disorder, BD）患者的自杀行为是多维度的复杂行为，涉及特定的神经内分泌与心理机制。既往研究提示，自杀型双相情感障碍患者可能存在海马亚区动态功能连接（dynamic functional connectivity, dFC）变异性异常，以及下丘脑-垂体-肾上腺（hypothalamic-pituitary-adrenal, HPA）轴活动异常，且该异常可能与自杀相关人格特质存在关联。本研究旨在验证这一假说。方法 本研究纳入79例双相情感障碍患者，其中39例有自杀未遂（suicidal attempt, SA）史，40例无自杀未遂史，另纳入35名健康对照者，采集所有受试者的静息态功能磁共振成像数据。通过检测清晨血浆促肾上腺皮质激素（adrenocorticotropic hormone, ACTH）与皮质醇（cortisol, CORT）水平，评估下丘脑-垂体-肾上腺轴的活动情况。所有参与者均采用明尼苏达多相人格量表第二版（Minnesota Multiphasic Personality Inventory-2, MMPI-2）完成人格评估。结果 与无自杀未遂史的双相情感障碍患者及健康对照者相比，有自杀未遂史的双相情感障碍患者右侧尾侧海马与左侧颞上回（superior temporal gyrus, STG）之间的动态功能连接变异性显著升高。有自杀未遂史的双相情感障碍患者的血浆ACTH水平显著低于健康对照者，且该水平与右侧尾侧海马-左侧颞上回的动态功能连接变异性呈正相关。有自杀未遂史的双相情感障碍患者的疑病、抑郁及精神分裂症维度得分显著高于无自杀未遂史的双相情感障碍患者。此外，多变量回归分析显示，在自杀型双相情感障碍患者中，ACTH与右侧尾侧海马-左侧颞上回动态功能连接变异性的交互作用可独立预测MMPI-2的抑郁维度得分。结论 本研究结果表明，自杀型双相情感障碍患者存在海马-颞叶皮层动态功能连接变异性升高，且下丘脑-垂体-肾上腺轴活动亢进程度更低，该异常可能会对其人格特质产生影响。