Adult attachment style is associated with cerebral μ‐opioid receptor availability in humans

Abstract

Human attachment behavior mediates establishment and maintenance of social relationships. Adult attachment characteristically varies on anxiety and avoidance dimensions, reflecting the tendencies to worry about the partner breaking the social bond (anxiety) and feeling uncomfortable about depending on others (avoidance). In primates and other mammals, the endogenous μ-opioid system is linked to long-term social bonding, but evidence of its role in human adult attachment remains more limited. We used in vivo positron emission tomography to reveal how variability in μ-opioid receptor (MOR) availability is associated with adult attachment in humans. We scanned 49 healthy subjects using a MOR-specific ligand [(11) C]carfentanil and measured their attachment avoidance and anxiety with the Experiences in Close Relationships-Revised scale. The avoidance dimension of attachment correlated negatively with MOR availability in the thalamus and anterior cingulate cortex, as well as the frontal cortex, amygdala, and insula. No associations were observed between MOR availability and the anxiety dimension of attachment. Our results suggest that the endogenous opioid system may underlie interindividual differences in avoidant attachment style in human adults, and that differences in MOR availability are associated with the individuals' social relationships and psychosocial well-being.

Variation in the β-endorphin, oxytocin, and dopamine receptor genes is associated with different dimensions of human sociality

“…The density of μ-opioid receptors has previously been found to be related to attachment style, though mainly with the avoidance dimension (32). Importantly, OPRM1 variation was also associated with both dyadic relationship quality and community integration, which may reflect the way social dispositions affect these higher-level outcomes.…”

“…Positron emission tomography (PET) and genetic studies have linked β-endorphin (μ-opioid) receptor variation with attachment style (31,32), with Significance Social behavior in mammals is underpinned by a number of social neuropeptides. Most studies, however, focus on a single neuropeptide (often oxytocin), and invariably only in the context of reproductive relationships.…”

Social Laughter Triggers Endogenous Opioid Release in Humans

“…In agreement with these findings, significant laughter-induced MOR activation was also observed in the anterior insula. The unmyeliated C-tactile fibers project to the insula, but not to the primary somatosensory cortices (Olausson et al, 2002), and this tactile system responding to slow, pleasurable stroking may provide the sensory pathway for emotional and affiliative touching. Along with prior functional imaging studies showing insula activation while subjects listen to vocal laughter bursts (Sander and Scheich, 2005), our data support the claim that social laughter may engage the same affectivesensory circuits as does physical grooming, which is consistent with Darwin's original proposal that laughter is a kind of "tickling of the mind" (Darwin, 1872).…”

‘Naltrexone Blocks Endorphins Released when Dancing in Synchrony’

“…Finally, the between-subject design in this experiment did not account for interindividual variation in opioid receptor availability and functioning, and capacity to experience social reward (Nummenmaa et al 2015;Troisi et al 2011;Way et al 2009). Variation in the μ-opioid gene and opioid receptor availability, for example, could have influenced the effects of naltrexone on individuals as well as influenced our measures of social closeness.…”