Central Institute of Mental Health, University of Heidelberg, Medical Faculty Mannheim, Mannheim, Germany.
Central Institute of Mental Health, University of Heidelberg, Medical Faculty Mannheim, Mannheim, Germany2now with Institute of Experimental Psychology, University of Regensburg, Regensburg, Germany.
JAMA Psychiatry. 2014 Jun;71(6):672-80. doi: 10.1001/jamapsychiatry.2014.35.
Relative risk for the brain disorder schizophrenia is more than doubled in ethnic minorities, an effect that is evident across countries and linked to socially relevant cues such as skin color, making ethnic minority status a well-established social environmental risk factor. Pathoepidemiological models propose a role for chronic social stress and perceived discrimination for mental health risk in ethnic minorities, but the neurobiology is unexplored.
To study neural social stress processing, using functional magnetic resonance imaging, and associations with perceived discrimination in ethnic minority individuals.
DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional design in a university setting using 3 validated paradigms to challenge neural social stress processing and, to probe for specificity, emotional and cognitive brain functions. Healthy participants included those with German lineage (n = 40) and those of ethnic minority (n = 40) from different ethnic backgrounds matched for sociodemographic, psychological, and task performance characteristics. Control comparisons examined stress processing with matched ethnic background of investigators (23 Turkish vs 23 German participants) and basic emotional and cognitive tasks (24 Turkish vs 24 German participants).
Blood oxygenation level-dependent response, functional connectivity, and psychological and physiological measures.
There were significant increases in heart rate (P < .001), subjective emotional response (self-related emotions, P < .001; subjective anxiety, P = .006), and salivary cortisol level (P = .004) during functional magnetic resonance imaging stress induction. Ethnic minority individuals had significantly higher perceived chronic stress levels (P = .02) as well as increased activation (family-wise error-corrected [FWE] P = .005, region of interest corrected) and increased functional connectivity (PFWE = .01, region of interest corrected) of perigenual anterior cingulate cortex (ACC). The effects were specific to stress and not explained by a social distance effect. Ethnic minority individuals had significant correlations between perceived group discrimination and activation in perigenual ACC (PFWE = .001, region of interest corrected) and ventral striatum (PFWE = .02, whole brain corrected) and mediation of the relationship between perceived discrimination and perigenual ACC-dorsal ACC connectivity by chronic stress (P < .05).
Epidemiologists proposed a causal role of social-evaluative stress, but the neural processes that could mediate this susceptibility effect were unknown. Our data demonstrate the potential of investigating associations from epidemiology with neuroimaging, suggest brain effects of social marginalization, and highlight a neural system in which environmental and genetic risk factors for mental illness may converge.
精神分裂症这种脑部疾病的相对风险在少数民族中增加了一倍以上，这种影响在各国都很明显，与肤色等与社会相关的线索有关，这使得少数民族身份成为一个既定的社会环境风险因素。病生流行病学模型提出，慢性社会压力和感知歧视与少数民族的心理健康风险有关，但神经生物学尚未得到探索。
使用功能磁共振成像研究神经社会压力处理，并研究其与少数民族个体感知歧视之间的关联。
设计、地点和参与者：在大学环境中进行的横断面设计，使用 3 种经过验证的范式来挑战神经社会压力处理，并探查特异性，即情绪和认知大脑功能。健康参与者包括具有德国血统的参与者（n=40）和来自不同种族背景的少数民族参与者（n=40），他们在社会人口统计学、心理学和任务表现方面相匹配。对照比较使用与调查员具有相同种族背景的人（23 名土耳其人对 23 名德国人）和基本情绪和认知任务（24 名土耳其人对 24 名德国人）来检查压力处理情况。
血氧水平依赖性反应、功能连接和心理及生理测量。
在功能磁共振成像压力诱发期间，心率显著增加（P<0.001），主观情绪反应（与自身相关的情绪，P<0.001；主观焦虑，P=0.006）和唾液皮质醇水平（P=0.004）。少数民族个体的慢性压力水平明显更高（P=0.02），并且前扣带回皮质（ACC）的围生带前部的激活（经校正的全脑错误校正[FWE]P=0.005，感兴趣区校正）和功能连接（PFWE=0.01，感兴趣区校正）也明显增加。这种影响是特定于压力的，不能用社会距离效应来解释。少数民族个体的感知群体歧视与围生带 ACC（PFWE=0.001，感兴趣区校正）和腹侧纹状体（PFWE=0.02，全脑校正）的激活之间存在显著相关性，并且感知歧视与围生带 ACC-背侧 ACC 连接之间的关系受慢性压力的调节（P<0.05）。
流行病学家提出了社会评价压力的因果作用，但介导这种易感性效应的神经过程尚不清楚。我们的数据表明，用神经影像学研究流行病学关联具有潜力，提示社会边缘化的大脑效应，并突出了一个神经系统，其中精神疾病的环境和遗传风险因素可能会汇聚。
