Genetics of adult attachment and the endogenous opioid system

Abstract

Since the pioneering work by Panksepp et al , the neurobiological bases of attachment behavior have been closely linked with opioid neurotransmission. Candidate gene studies of adult individuals have shown that variation in the mu-opioid receptor gene ( OPRM1 ) influences attachment behavior. Early maternal care and the A/A genotype of the A118G polymorphism interact in modulating levels of fearful attachment. Compared to their counterparts carrying the A/A genotype, individuals expressing the minor 118G allele show lower levels of avoidant attachment and experience more pleasure in social situations. Brain imaging research has strengthened the biological plausibility of candidate gene studies. The avoidance dimension of attachment correlates negatively with mu-opioid receptor availability in the thalamus and anterior cingulate cortex, as well as the frontal cortex, amygdala, and insula. Overall, findings from human studies combined with those from animal models suggest that research on the genetic bases of attachment should include the endogenous opioid system among the investigated variables.

Re‐wiring of the bonded brain: Gene expression among pair bonded female prairie voles changes as they transition to motherhood

“… 88 Of special interest is the role of mu‐opioid receptors in mediating social attachment. 89 , 90 , 91 For instance, primate studies have showed that allelic differences in the oprm1a gene predict differences in affiliative behavior 92 , 93 and maternal motivation to prevent separation from infants. 94 Moreover, the ACC contains a high density of opioid receptors 95 , 96 and binding of these receptors is critical for processing the hedonic value of an environment and maintaining a cue's conditioned rewarding effects.…”

“…Opioidergic activity in the ACC is important for the regulation of affective states 88 . Of special interest is the role of mu‐opioid receptors in mediating social attachment 89–91 . For instance, primate studies have showed that allelic differences in the oprm1a gene predict differences in affiliative behavior 92,93 and maternal motivation to prevent separation from infants 94 .…”

Influence of anxious attachment on the relationship between primary emotions and substance-related addictive behaviors

“…Our findings are not only consistent with the conceptualization of anxious attachment as an hyperactivation strategy, but also with the assumptions of Liese et al ( 39 ), who hypothesizes that insecure attachment, in particular anxious attachment and related emotion regulation deficits, might be a psychological characteristics that increase risk for substance related addictions. Moreover, previous research has observed considerable heritability of both adult attachment ( 42 ) and primary affect dispositions ( 54 ) and highlighted links between insecure attachment and candidate genes related to oxytocin and mu-opioid receptors ( 42 , 43 ). Hence, a next research step might be the investigation of shared genetic markers for both adult attachment and primary affect dispositions, which could serve as the biological foundation of the psychometrical associations observed in the present and previous studies ( 44 ).…”

“…Of note, recent evidence regarding the genetic underpinnings of adult attachment highlight not only candidate genes related to oxytocin pathways and brain-derived neurotrophic factor ( 42 ) but also the involvement of the mu-opioid receptor gene ( 43 ), especially in regards to avoidant attachment. The shared neurobiological underpinnings linked to the endogenous opioid system might in part explain previously observed associations between adult attachment and SADNESS dispositions ( 44 ).…”