Research suggests that endogenous opioids play a key role in the creation and maintenance of attachment bonds. Opioids acting at the μ-opioid receptor mediate reward and analgesia and are thus thought to underlie feelings of comfort and warmth experienced in the presence of close others. Disruption of μ-opioidergic activity increases separation distress in animals, suggesting that low opioid states may contribute to social pain. Accordingly, a functional μ-opioid receptor (OPRM1) polymorphism (C77G in primates, A118G in humans) affecting opioidergic signaling has been associated with separation distress and attachment behavior in nonhuman primates, and social pain sensitivity in humans. However, no research has examined the effects of this polymorphism on socioemotional experience, and specifically felt security, in daily interactions between romantic partners. Using an event-contingent recording method, members of 92 cohabiting romantic couples reported their felt security and quarrelsome behavior in daily interactions with each other for 20 days. Consistent with prior work, findings suggested that, relative to AA homozygotes, G allele carriers were more sensitive to their partners’ self-reported quarrelsome behaviors (e.g., criticism), showing a greater decline in felt security when their partners reported higher quarrelsome behavior than usual. This is the first study to link variation in OPRM1 with felt security toward romantic partners in everyday social interactions. More generally, this research supports the theory that the attachment system incorporated evolutionarily primitive pain-regulating opioidergic pathways. We also discuss implications of this work for understanding of differential vulnerability to health risks posed by social stress.

研究表明，内源性阿片类药物在依恋关系的建立和维持中起着关键作用。作用于 μ-阿片受体的阿片类药物可介导奖赏和镇痛作用，因此被认为是亲近他人在场时所体验到的舒适感和温暖感的基础。μ-阿片能活动的中断会增加动物的分离痛苦，这表明低阿片类药物状态可能会导致社会痛苦。因此，功能性μ-阿片受体（OPRM1) 影响阿片能信号的多态性（灵长类动物中的 C77G，人类中的 A118G）与非人类灵长类动物的分离痛苦和依恋行为以及人类的社会疼痛敏感性有关。然而，还没有研究考察这种多态性对社会情感体验的影响，尤其是在浪漫伴侣之间的日常互动中对安全感的影响。使用事件偶然记录方法，92 对同居浪漫情侣的成员报告了他们在 20 天的日常互动中的安全感和争吵行为。与之前的工作一致，研究结果表明，相对于 AA 纯合子，G 等位基因携带者对其伴侣自我报告的争吵行为（例如批评）更敏感，当他们的伴侣报告比平时更多的争吵行为时，他们的安全感下降得更多。这是第一项将变异与OPRM1在日常社交互动中对浪漫伴侣感到安全。更一般地说，这项研究支持这样的理论，即依恋系统结合了进化上原始的疼痛调节阿片能途径。我们还讨论了这项工作对理解社会压力造成的健康风险的不同脆弱性的影响。