Narcissistic Personality Disorder (NPD) entails severe impairments in interpersonal functioning that are likely driven by selfish and exploitative behavior. Here, we investigate the underlying motivational and neural mechanisms of prosocial decision-making by experimentally manipulating motivational conflict between selfish and prosocial incentives. One group of patients diagnosed with NPD and a group of healthy controls (CTL) were scanned using functional magnetic resonance imaging while performing a prosocial decision-making task. In this task, we systematically varied the level of conflict between selfish and prosocial options on each trial. We analyzed choice behavior, response times, and neural activity in regions associated with conflict monitoring to test how motivational conflict drives prosocial choice behavior. Participants in the NPD group behaved less prosocially than the CTL group overall. Varying degrees of motivational conflict between selfish and prosocial options induced response variability in both groups, but more so in the CTL group. The NPD group responded faster than the CTL group, unless choosing prosocially, which slowed response times to a level comparable to the CTL group. Additionally, neural activity tracking motivational conflict in dorsomedial prefrontal cortex was reduced in the NPD group. Collectively, low generosity in NPD appears to arise from reduced consideration of prosocial motives, which obviates motivational conflict with selfish motives and entails reduced activity in neural conflict monitoring systems. Yet, our data also indicate that NPD is not marked by an absolute indifference to others' needs. This points to potentials for improving interpersonal relationships, effectively supporting the well-being of patients and their peers.

中文翻译：

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自恋与亲社会动机之间在自恋型人格障碍中的冲突的额叶皮质追踪减少

自恋型人格障碍（NPD）导致人际交往功能严重受损，这很可能是由于自私和剥削行为所致。在这里，我们通过实验操纵自私和亲社会激励之间的动机冲突，来研究亲社会决策的潜在动机和神经机制。在执行亲社会决策任务的同时，使用功能磁共振成像对一组诊断为NPD的患者和一组健康对照（CTL）进行扫描。在这项任务中，我们在每次审判中系统地改变了自私和亲社会选择之间的冲突程度。我们分析了与冲突监控相关的区域中的选择行为，响应时间和神经活动，以测试动机性冲突如何驱动亲社会的选择行为。NPD组的参与者在总体上比CTL组的行为更不友好。自私和亲社会选择之间不同程度的动机冲突导致两组的反应差异，但在CTL组则更为明显。NPD组的反应比CTL组更快，除非选择亲切地选择，这会使响应时间减慢到与CTL组相当的水平。此外，NPD组减少了跟踪背部前额叶皮层的神经活动的动机冲突。总的来说，NPD的低度慷慨似乎是由于减少了对亲社会动机的考虑，从而消除了与自私动机的动机冲突，并减少了神经冲突监控系统的活动。然而，我们的数据还表明，NPD并没有以对他人需求的绝对漠不关心为标志。