Contact: Markus Heinrichs, PhD
University of Zurich/Switzerland
Phone: 0041-1-634-4457
Email: mhein@klipsy.unizh.ch
Embargoed until: March 9, 2001

MONTEREY, CA-- Did you ever notice that having a good friend present helps calm you? What does social support trigger in the human brain to enable you to control physiological reactions in stressful situations? A single hormone could play a key role in the human psychobiology of stress protection and seems to enable us to make optimal use of social support.

That is the finding of a study on moderators of physiological reactions to stress conducted by Markus Heinrichs, Ph.D., Assistant Professor in the Department of Clinical Psychology at the University of Zurich, Switzerland. Results of the study were presented for the first time at the American Psychosomatic Society Annual Meeting, held March 7-10 in Monterey, CA.

The investigation was designed to assess the effects of social support and a hormone that is associated with stress protection on the ability to cope with stressful situations. Besides the well known effect of support, Heinrichs and his colleagues were interested in the modulating effects of the hormone oxytocin and, especially, in their combined effects.

"Oxytocin is a hormone well known for its role in fascilitating the milk ejection reflex during lactation and in stimulating uterine contractions during parturition. Recent studies in animals suggest that oxytocin has also strong stress protective effects and is associated with social attachment," Heinrichs said.

The study involved 40 healthy men who performed a psychological stress test routinely used by researchers to stimulate stress responses (unprepared speech and mental arithmetic in front of an audience). Participants received either the hormone oxytocin or placebo as an intranasal spray, and either no social support or social support from their best friend. Support providers were instructed to offer both instrumental and emotional support during a 10-minute period before stress.

Results showed that under stressful conditions participants received the least benefit from having only the nasal spray containing the hormone, and the most benefit when they had both hormone and social support. "In this study, the combination of the intranasally administered hormone and social support by the best friend was more effective than only support in controlling physiological reactions in a stressful situation. Although there was no stress suppressive effect of oxytocin alone, the hormone reinforced the protective effect of social support," Heinrichs said. "From these results we conclude that the hormone oxytocin plays a central role in the biology of human stress management. Further research has to clarify whether patients with stress-related psychiatric and psychosomatic disorders show dysfunctions in the oxytocin system or might benefit from pharmacological intervention."

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