Oxytocin: The cuddle hormone makes a detour

19. October 2012
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A few breathfuls of hormone concentrate and a chance encounter becomes a love affair full of empathy. The marketing slogans for oxytocin lotions are not only wrong – oxytocin probably has an effect only in certain cases.

When the term “love hormone” comes up, many know what is meant by this. Oxytocin is much more effective than large amounts of alcohol in putting the person in front of you in the best light. With a bit of the brilliant substance in our noses we quickly have more confidence even with strangers. DocCheck reported in 2010 on a study in which an aerosol conferred upon men a sensitivity, which is otherwise only known with women. Anyone browsing the net quickly finds dubious sources, which despatch the miraculous substance at a not exactly cheap price. Liquid Confidence for women and men, it says in advertising.

Researchers know better

Can the medical world use oxytocin for problem cases involving people who have difficulties in socialising and behavioral disorders in their social behaviour? It would be nice if it were as simple as is made out in internet advertising – and once existed as part of the wishful thinking of some oxytocin researchers only a few years ago. “Oxytocin is not the magic bullet that makes everyone happy and sociable“, says one person who probably knows more than most about it. Mark Henry of the University of Freiburg has studied the neuropeptide for more than ten years. He also knows the dark side, which in previous studies were rarely mentioned – and were perhaps not even considered.

Unexpected effect: envy and “schadenfreude”

In 2009 in the “Journal of Biological Psychiatry” there appeared a report by Simone Shamay-Tsoory from the University of Haifa. While playing, a pinch of the hormone caused an increase in envy directed at the winner of gambling games as well as a sense of glee in the victory. But that was only one of the first reports that shook confidence in the “star hormone”. Jennifer Bartz from Mount Sinai School of Medicine in New York found that oxytocin produced exactly the opposite of the desired effect with particularly anxious and socially-sensitive people: it decreased their trust and willingness to cooperate.

No consensus found

Similar results were also arrived at by Carolyn de Clerck of the University of Antwerp. Trust and willingness to cooperate rise with oxytocin only if we have at least a basic level of knowledge of our partner-to-be. Anonymous stranger cannot benefit from this “sympathy enhancement”. This goes so far that Carsten de Dreu of the University of Amsterdam believes that oxytocin can bring about nationalistic characteristics. Name of the same nationality seem more likable, but German or Oriental ones seem rather disgusting to the study participants. Nonetheless, other researchers put the broad conclusions of the Amsterdam group in question. After another “Science”-paper from the de Dreu group it really seems to be the case that oxytocin increases trust within a group, but that trust is rather lessened toward outsiders.

From social avoider to social professional?

Whenever one knows another person, using oxytocin one can probably look that person more closely in the eye and can read his feelings there. Jennifer Bartz is convinced of this. For the contact-shy, oxytocin is probably not the way to becoming a social butterfly. Especially since other factors are also involved which are predetermined by the genes and are only subject to influence to a limited extent, because the oxytocin receptor is polymorphic. A point mutation determines the function of the confidence conveying agent. In stressful situations, Mark Heinrichs and his team found out, cortisol levels did not decrease in subjects with the A receptor variant despite use of the hormone. It was precisely this group in other studies compared with “G” which had more problems with empathy and had a more pessimistic view of life. When necessary, people who have a “G” in the right place in the receptor are more willing in a problematic moment to turn to their friends.

Sex chromosome as another influencing factor

And still another significant difference in gene features influence the hormone effect: the Y chromosome. The response to a threat in the form of a particular grimace steers oxytocin in very different directions according to gender. In men, it reduces the activity of the amygdala, our “feeling assessment center”, in women it increases its activity. Therefore oxytocin would for them in particular carry the function of prewarning for dangers. During conflicts in a relationship as well, the genders react differently to a hormone surge: In women, the α-amylase levels decrease in proportion to the activity of the sympathetic nervous system, for men the tendency toward outbursts of emotion rises in parallel with the enzyme level, as does also positive behaviour during the couple’s quarrel.

One feature, many applications

This rather simple kind of neuropeptide is – from an evolutionary point of view – prehistoric and occurs for example also in an invertebrate such as the octopus. The first insights into the function are however provided by voles. Prairie voles are lifelong monogamous and take care of their young together. It comes as no surprise, therefore, that there is high hormone receptor expression in the reward centre of their brain. Their relatives in the mountains do not by contrast have such a firm commitment to and allocation of tasks in parenting. Their hormone receptor levels are significantly lower than that of their relatives. With a blocking of the receptor, from the prairie mouse a mountain mouse can be made – or at least as far as personality goes.

Oxytocin plays a major role in the climax of sexual intercourse as well as in lactogenesis of breastfeeding or at the onset of labor pains. It seems that the hormone has over its history acquired many functions. The base function nevertheless is in all likelihood always based on a strengthening of the social bond within the circle and building trust – probably via its influence in the amygdala.

Remedy for depression and autism?

Whether this effect can also help patients with autism or its related spectra of conditions is something being worked on at the moment by quite a number of research scientists. The scientists in Freiburg also have patients with depression and borderline personality disorder in sight, clinical trials on this have already begun. “From the early data however”, says Markus Heinrichs, “we can clearly recognise that oxytocin alone does not straighten things out”. Only together with psychotherapy could the new strategy offer a real alternative to existing antidepressants – because, unlike drugs used until now, oxytocin directly attacks the cause of the disturbances.

Not effective enough

“I can explain the effects seen in Heinrichs’ studies by the fact that oxytocin binds to receptors in the rest of the body, where it reduces intestinal activity, slightly lowers blood pressure, and decreases cortisol levels. Thus, the subjects feel relaxed and show more social patterns of behavior.” Valerie Grinevich of the Max Planck Institute for Medical Research in Heidelberg has doubts as to whether the oxytocin spray even finds its way into the brain at all, for experiments in rats indicate to her that in several brain regions oxytocin only works if the original product comes from the nerve cells of the environment.

What is certain in any case is that the even recently acclaimed miracle drug does not make everybody happy, capable of bonding and of having trusting relationship. The effect depends on the previous experience of the subject, his or her environment and, not least, his or her genetic map.

Mark Heinrichs puts it dramatically and realistically: “If you sit at home with a social phobia and someone prescribes you oxytocin – I bet the only effect that the you will feel is a runny nose”.

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2 comments:

dr. Judit Felméri
dr. Judit Felméri

And what about the rising number of autistic children? Is there any connection between the increasing amount of oxytocin-induced labours and autism?

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Public Health Nurse II Beverly Pirtle
Public Health Nurse II Beverly Pirtle

So, how does the lack of oxytocin at a non-labor C-section birth affect the very foundation of the mother/baby relationship? Especially if that baby is not breastfed? Hmmm? Please don’t assume anything until you have thoroughly studied the individuals that have experienced this. It is going to be a narrow, decreasing range of subjects, since the majority of C-section moms breastfeed their babies these days (Michel Odent, MD). The turnaround happened around 1980.

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