Hormone found to affect bonding

The hormone best known for its role in orgasms and labor may influence our ability to bond with others, according to researchers at the University of California, San Francisco. In a preliminary study, the hormone oxytocin was shown to be associated with the ability to maintain healthy interpersonal relationships and healthy psychological boundaries with other people. The study appears in the July issue of Psychiatry. "This is one of the first looks into the biological basis for human attachment and bonding," said Rebecca Turner, adjunct assistant professor of psychiatry and lead author of the study. "Our study indicates that oxytocin may be mediating emotional experiences in close relationships."The study builds upon previous knowledge of the important role oxytocin plays in the reproductive life of mammals. The hormone facilitates nest building and pup retrieval in rats, acceptance of offspring in sheep and the formation of adult pair-bonds in prairie voles. In humans, oxytocin stimulates milk ejection during lactation, uterine contraction during birth and is released during sexual orgasm in both men and women.In the new study, 26 non-lactating women between the ages of 23 and 35 were asked to recall a past relationship event that was associated with positive emotions, such as love or infatuation, and then a negative emotion, such as loss or abandonment.