Biology of social bonds.

A hormone that helps initiate the process of childbirth and surges during sexual orgasm also takes part in women's ability to forge close relationships, preliminary data suggest.

Women who report having satisfying friendships and a committed sexual relationship exhibit large jumps in blood concentrations of this hormone, oxytocin, as they experience positive emotions, asserts a team led by psychologist Rebecca A. Turner of the California School of Professional Psychology in Alameda. Resting oxytocin concentrations remain stable for these women as they endure negative emotions, Turner's/ group reports in the Summer PSYCHIATRY.

In contrast, women who describe having lifelong troubles with close relationships and who have no current sexual partner show, during positive moods, oxytocin concentrations no higher than those measured at rest. Moreover, their oxytocin readings decline markedly after the onset of negative feelings.

"Oxytocin may be mediating emotional experiences in close relationships," Turner holds.

Oxytocin contributes to maternal and reproductive behavior in mammals, although the extent of its influence is unclear (SN: 10/19/96, p. 246). It fosters nest building and pup retrieval in rats and the creation of lasting sexual partnerships in prairie voles.

Turner and her coworkers asked 25 healthy women, ages 23 to 35, first to think briefly about a past love or infatuation that incited pleasant emotions and then to consider a prior, upsetting experience of lost love or abandonment.

Separately, each volunteer also received a massage of the neck and shoulders from a masseuse. Earlier studies suggested that stimulation of this kind boosts blood-oxytocin values.

The scientists took blood samples before, during, and after each of the three experimental conditions. Participants also filled out questionnaires about their intimate relationships.

Women whose oxytocin measurements rose when thinking about a positive relationship had a similar response to massage. Their questionnaires revealed considerable skill at handling close relationships and comfort with being alone. Those whose oxytocin amounts fell during negative emotion maintained resting levels of the hormone during massage. They said that they usually felt anxious in close relationships.

Further research should explore oxytocin patterns in people with depression and other mental disorders marked by in, tense social anxiety, the investigators propose,