Long-term oxytocin administration enhances the experience of attachment

The neuropeptide 'oxytocin' (OT) is known to play a pivotal role in a variety of complex social behaviors by promoting a prosocial attitude and interpersonal bonding. Previous studies showed that a single dose of exogenously administered OT can affect trust and feelings of attachment insecurity. With the present study, we explored the effects of two weeks of daily OT administration on measures of state and trait attachment using a double-blind between-subjects randomized placebo-controlled design. In 40 healthy young adult men state and trait attachment were assessed before and after two weeks of daily intranasal OT (24 IU) or placebo using the State Adult Attachment Scale and the Inventory of Parent and Peer Attachment. Mood, social responsiveness and quality of life were additionally assessed as secondary outcome measures. Reductions in attachment avoidance and increases in reports of attachment toward peers were reported after two weeks of OT treatment. Further, treatment-induced changes were most pronounced for participants with less secure attachment towards their peers. indicating that normal variance at baseline modulated treatment response. OT treatment was additionally associated with changes in mood, indicating decreases in feelings of tension and (tentatively) anger in the OT group, not in the placebo group. Further, at the end of the two-week trial, both treatment groups (OT, placebo) reported to experience an increase in social responsiveness and quality of life, but the effects were only specific to the OT-treatment in terms of reports on 'social motivation'. In summary, the observed improvements on state and trait dimensions of attachment after a multiple-dose treatment with OT provide further evidence in support of a pivotal role of OT in promoting the experience of attachment. (C) 2017 Elsevier Ltd. All rights reserved.