During the past few years, the brain hormone oxytocin has received quite a
bit of attention in the popular press. For instance, an article in the New
York Times reported that "the compound can spur an overwhelming
urge to cuddle," and "in some cases, it works as an
aphrodisiac...." An article in New Scientist reported that
oxytocin "peaks with orgasm, makes a loving touch magically melt away
Moreover, oxytocin perfume is even being sold to the public over the
Internet. Whether it is worth the hype that it's getting is unclear. One
oxytocin researcher—David Feifel, M.D., Ph.D., a professor of psychiatry
at the University of California, San Diego—is unconvinced, and another
oxytocin scientist—Markus Heinrichs, Ph.D., a professor of clinical
psychology and psychobiology at the University of Zurich in
Switzerland—agreed: "There is no reason to believe that oxytocin
on the skin or clothes should significantly change behavior." But one
thing is for sure: oxytocin does indeed have some provocative properties,
animal and clinical research is showing.
True, oxytocin has long been known to be crucial for labor prior to the
birth of a baby and for the breast feeding that comes after a baby is born.
But in recent years it has also been found to enhance social interactions and
the formation of attachments in both experimental animals and humans. And
during the past decade, the means whereby oxytocin acts as a social catalyst
have become increasingly evident.
For example, oxytocin seems to promote social interactions by promoting
social recognition. Thomas Insel, M.D., director of the National Institute of
Mental Health, and colleagues reported in the July 2000 Nature
Genetics that mice lacking the gene for oxytocin experienced social
amnesia—that is, they failed to recognize mice they had already met
(Psychiatric News, July 2,
Oxytocin also seems to promote social interactions by increasing people's
trust in others. Michael Kosfeld, Ph.D., of the Center for the Study of Social
and Neural Systems at the University of Zurich in Switzerland, along with
other researchers, reported in the June 2, 2005, Nature that male
subjects who inhaled a nasal spray spiked with oxytocin gave more money in a
risky investment game than did male subjects who sniffed a spray containing no
Still other ways in which oxytocin works as a social catalyst appear to be
by helping people intuit the mental state of others, increasing a person's
gaze toward the eye region of another person, and getting a person to remember
positive rather than negative encounters with another person. These results,
from Gregor Domes, Ph.D., of Rostock University in Germany, and colleagues and
from Adam Guastella, Ph.D., of the University of New South Wales in Australia,
and colleagues were published in the March 15, 2007, January 1, 2008, and
August 1, 2008, issues of Biological Psychiatry.
But perhaps the most critical means whereby oxytocin brings people together
is by reducing anxiety, experts suggest.
Donatella Marazziti, M.D., a psychiatrist at the University of Pisa in
Italy, reported in the October 2006 Clinical Practice and Epidemiology in
Mental Health a significant link between blood levels of oxytocin and
anxiety over romantic attachment in human subjects—that is, the greater
the anxiety, the higher the oxytocin levels. Since animal research has shown
that oxytocin has antianxiety properties, it's quite possible that people in
the throes of romance produce a surplus of oxytocin to quell their anxiety,
Marazziti told Psychiatric News.
And the means by which oxytocin dampens anxiety may be by cooling the
amygdala, the brain's fear center, Andrews Meyer-Lindenberg, M.D., Ph.D., of
the National Institute of Mental Health and colleagues reported in the
December 7, 2005, Journal of Neuroscience. Thomas Baumgartner, Ph.D.,
of the Center for the Study of Social and Neural Systems at the University of
Zurich in Switzerland, and his colleagues reported similar findings in the May
Not surprisingly, such findings are stimulating efforts to see whether
oxytocin might work as an antianxiety medication.
For example, Pradeep Nathan, Ph.D., of the University of Cambridge in
England, and his colleagues are undertaking a trial to find out whether
intranasally delivered oxytocin can attenuate fear in subjects with social
anxiety disorder. "We should have some data by July 2009," he told
Heinrichs and coworkers are conducting a clinical trial to see whether
oxytocin can help people with generalized anxiety disorder. "We expect
data early in 2009," he said. They are also conducting a trial to see
whether oxytocin combined with cognitive-behavioral therapy might also benefit
such individuals, he added.
Robert Ring, Ph.D., head of molecular neurobiology at Wyeth Research in
Princeton, N.J., and coworkers have found that an oxytocin receptor agonist
called WAY-267464 produces, in experimental animals, antianxiety effects
similar to those produced by oxytocin itself.
Oxytocin also looks promising as a new type of treatment for the social
deficits experienced by persons with autism spectrum disorders. Eric
Hollander, M.D., chair of psychiatry at Mount Sinai School of Medicine in New
York City, and colleagues tested the ability of 15 adults with an autism
spectrum disorder to detect the emotional intonations of
sentences—expressing, say, anger, sadness, or happiness—a task in
which they typically have difficulty. The researchers then gave the subjects
intravenous infusions of a placebo or infusions of oxytocin and repeated the
tests. Finally, the researchers compared the before-and-after results under
both the oxytocin and placebo conditions.
The subjects improved their ability to detect emotions in speech under both
conditions. However, their ability was more enduring under the influence of
oxytocin. "These results are consistent with studies linking oxytocin to
social recognition in rodents as well as studies linking oxytocin to prosocial
behavior in humans and suggest that oxytocin might facilitate
social-information processing in those with autism," Hollander and his
team concluded in the February 15, 2007, Biological Psychiatry."
These findings also provide preliminary support for the use of oxytocin
in the treatment of autism."
In fact, Hollander and his group are now conducting a randomized,
double-blind, placebo-controlled trial to explore the long-term therapeutic
benefits of oxytocin in autism subjects. Also, this time oxytocin will be
given intranasally instead of by injection.
It's even possible that oxytocin might enhance social behavior in
individuals with schizophrenia. David Feifel, M.D., Ph.D., a professor of
psychiatry at the University of California, San Diego, and coworkers are
recruiting subjects for a clinical trial to test the value of oxytocin as an
add-on treatment for schizophrenia.
So, what is oxytocin's future as an antianxiety, social-promoting
medication? Is it possible that it might become clinically available within
the next decade to treat persons who are anxious and/or socially
impaired—say, those with social anxiety disorder, generalized anxiety
disorder, autism, or schizophrenia?
"Following appropriate clinical trials, yes," Hollander told
Feifel thinks so too, although "it may not be oxytocin, but a
proprietary analog" that receives Food and Drug Administration approval,
On the whole, the oxytocin story "is a great story," Ring said."
We are all excited by the recent increase in reports from small
clinical studies investigating the effects of synthetic oxytocin on central
nervous system function in human subjects,... [and] I think it may go
But unfortunately, he added, the oxytocin receptor agonist WAY-267464"
does not have any of the attributes that you would look for in a
clinical [drug] candidate,... and it is important for the field to appreciate
the practical limitations of using synthetic oxytocin as an actual treatment
approach for chronic central nervous system disorders."
For example, when synthetic oxytocin is delivered orally, only a small
amount reaches the brain, and when it is given intranasally, it has only
short-term effects. Actually, a biotechnology firm located in Bothell,
Wash.—MDRNA Inc.—was planning to try to create a long-acting
inhaled form of synthetic oxytocin, but then it shelved this program, Matthew
Haines, senior director of corporate communications for MDRNA, told
Psychiatric News. "We have changed our focus as a company from
the intranasal delivery of proteins and peptides to the development of
RNA-interference therapeutics," Haines explained
Nonetheless, MDRNA's program to develop a long-lasting intranasal form of
synthetic oxytocin is "available for outlicensing," Haines added.▪