Adult Attachment System Links with Brain μ-Opioid Receptor Availability in vivo

Abstract Background Secure attachment is important in maintaining individual’s health and well-being. Attachment disturbances increase the risk for developing different psychiatric disorders such as affective disorders. Yet, the neurobiological correlates of human attachment is poorly understood at the neurotransmitter level. We investigated whether adult attachment style is linked to functioning of the opioid and serotonergic systems in the human brain Methods We used positron emission tomography (PET) with radioligands [11C]carfentanil and [11C]MADAM to quantify μ–opioid receptor (N=39) and serotonin transporter (N=37) availability in volunteers with no current psychiatric disorders. Attachment style was determined according to the Dynamic-Maturational Model of attachment and adaptation with the structured Adult Attachment Interview (AAI) Results Secure attachment was associated with higher μ-opioid receptor availability in the hippocampus, amygdala, thalamus and prefrontal cortex when compared to insecure (i.e., avoidant or ambivalent groups combined) attachment. In contrast, attachment style was not associated with serotonin transporter availability Conclusions Our results provide preliminary in vivo evidence that the opioid system may be involved in the neurocircuits associated with individual differences in adult attachment behavior. The results suggest that variation in μ–opioid receptor availability may be linked with the individuals’ social relationships and psychosocial well-being and thus contributes to risk for psychiatric morbidity.