The Multiple Faces of “Love Hormone” Oxytocin


Oxytocin acquired the title of “love hormone” when it was discovered that it influenced parental — especially the connection between mother and child — and romantic bonding. But now researchers have discovered that it also influences social communications, the dynamics of in- and out-group relationships, and social stress. Scientists also believe that abnormal functioning of the oxytocin neural pathway may aggravate the symptoms of communications and social skills disorders associated with mental diseases like autism and schizophrenia.

New Insights into Oxytocin’s Role in Maternal Behavior

Scientists knew that oxytocin had a role to play in strengthening the bond between mother and child. But now they have found out that oxytocin also affects neural signals in the brain of the mother and influences her social responses.

In an experiment conducted on laboratory mice with pups, scientists discovered that when the little ones were separated from their mums, they produced ultrasonic SOS calls. The mother mouse picked up these signals to locate her pups. The mother mice responded similarly — started looking for their pups — when the scientists played the pup distress calls on speakers.

The scientists investigated how oxytocin is involved in this behavior.

The left auditory cortex of the brain receives the sound signals. This part of the brain has a large number of oxytocin receptors. The hormone levels increased in the mother mice when they heard the distress calls of their pups. Oxytocin not only made the mother mice respond to their pups but also inhibited her brain’s ability to process other social signals.

In the above experiment, it was also found that female mice without pups did not respond to distress calls made by pups of other mice. But when they were injected with oxytocin, they responded to the distress calls by rushing to search for and rescue the pups even though those were not their own.

This newly-discovered role of oxytocin is, however, not surprising. After all, babies are helpless and unable to defend themselves if they are separated from their mums. So it seems natural that nature intended oxytocin to exert influence on mothers in this way.

Oxytocin and Our Responses to Social Stimuli

The oxytocin system is critical to the expression of three basic social bonds — parental, filial, and romantic. According to one study, the levels of oxytocin remain more or less stable in individuals over extended periods of time and go on to play crucial role in the expression of other types of social attachment behavior later in their lives.

Scientists also believe that oxytocin interacts with neural, physical, and mental factors to develop unique expressions of social cognition and empathy in humans. For instance, scientists have discovered that the quality of early-life parental care tends to influence the way children form attachments in adulthood.

In 2005, an interesting study was conducted on two groups of children. The kids in one group were raised by their biological parents. The children in the other group were adopted, but they had been raised in orphanages where they were deprived of the typical care-giving environment that the children of the other group were raised in. The oxyotcin levels in the children from both groups were monitored when they were in contact with their mothers—biological or adopted. It was found that the children who were raised by their biological parents showed an increase in oxytocin levels while levels in the other group of children remained constant. So it is evident that early-life social experience influences the way individuals form relationships later on in their lives.

The above findings led scientists to explore the connection between oxytocin and social disorders that develop during childhood, like autism spectrum disorders. And, to their surprise, they also found out that oxytocin plays a role in managing the symptoms of certain mental illnesses like schizophrenia.

Oxytocin and Mental Illnesses

The “love hormone” oxytocin floods us with feel-good vibes. It has another beneficial face too.

According to a recent study, intranasal administration of oxytocin can improve the ability of schizophrenia patients to recognize negative emotions, like fear, in other people. It was found during the study that schizophrenia patients whose baseline performance was below median level showed greater improvement when they were administered oxytocin compared to patients who were more capable.

These findings have already unleashed a slew of research into the various aspects that need to be considered before administering oxytocin for therapeutic purposes to patients suffering from mental illnesses. For instance, one study suggests that the efficacy of intranasal administration of oxytocin is dependent on gender, hormonal and genetic profiles, and attachment history. Other scientists have investigated the effects of different doses of oxytocin on patients.

These studies are crucial for finding out how long the effects of oxytocin stays in laboratory patients because elevated levels of oxytocin can also trigger anxiety.

The Adverse Effects of Oxytocin

The “love hormone” oxytocin has been found to have a disturbing effect as well when present in more-than-normal amounts in the human body. For instance, it was shown that oxytocin also influences the memory. In an experiment conducted on laboratory mice, it was found that under conditions of social stress oxytocin fires the lateral septum region of the mouse brain, a region that intensifies memories. This means that oxytocin turns a stressful experience into a long-standing painful memory that can trigger anxiety and fear every time an individual confronts similar stressors in future. Chronic anxiety and fear can also lead to depression.

In another study, it was found that women who reported less-than-satisfactory quality of relationships with their partners and longer periods of time in their lives spent without romantic attachments had more oxytocin and the stress hormone cortisol than women who enjoyed more satisfying relationships.

These findings seem crucial considering that scientists are also toying with the idea of using oxytocin to manage the anxiety symptoms. It is evident that oxytocin is not only associated with good and happy feelings.

The discovery of new faces of oxytocin presents intriguing avenues for further study. These studies should help scientists and psychiatrists better understand and accurately analyze why we behave the way we do in specific social situations and with other human beings.


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Image via Svetlana Fedoseyeva / Shutterstock.

Viatcheslav Wlassoff, PhD

Viatcheslav Wlassoff, PhD, is a scientific and medical consultant with experience in pharmaceutical and genetic research. He has an extensive publication history on various topics related to medical sciences. He worked at several leading academic institutions around the globe (Cambridge University (UK), University of New South Wales (Australia), National Institute of Genetics (Japan). Dr. Wlassoff runs consulting service specialized on preparation of scientific publications, medical and scientific writing and editing.
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