Oxytocin: of human bonding and puppy dog eyes

Oxytocin, the so-called “bonding hormone”, is a neuromodulator released into the blood in a wide range of situations, many of which are involved in human interaction — interactions between sexual partners, between parents and their children, and within social groups. It helps human relationships by stimulating feelings such as trust, contentment, empathy, generosity and by reducing fear and anxiety.

It has been suggested that the way oxytocin helps human interaction means that it could perhaps have a future use in treating eating disorders and other mental health problems that involve antisocial behaviour or a sense of isolation in the sufferer.

Scientists have experimented with oxytocin as a treatment for everything from autism to schizophrenia, and researchers at New York University recently suggested that the way it amplifies neural signals in the brain means it could one day be used to treat social anxiety, post-traumatic stress disorder, speech and language disorder and even psychological issues stemming from child abuse.

Meanwhile, researchers at King’s College London have been studying the use of an oxytocin nasal spray in the treatment of anorexia nervosa. The low levels of oxytocin usually found in anorexia patients was initially considered to be just a secondary effect of starvation. But because low oxytocin is associated with increased anxiety and depression, the King’s researchers are investigating whether administering the hormone will help patients become more interested in connecting with others and be better able to manage social anxiety, which could be an important bridge to recovery.

In a double-blind trial, sufferers and a control group were given either oxytocin or a placebo and then subjected to a series of computerised tasks designed to test their social and sensory reactions. The research shows that oxytocin reduced patients’ unconscious tendencies to focus on food and body shape and negative emotions such as disgust.

Another intriguing study, by researchers in Japan, has shown that oxytocin can be involved in interaction across species boundaries. Their findings were reported recently in Science, under the snappy title ‘Oxytocin-gaze positive loop and the coevolution of human-dog bonds’.

The researchers collected urine from a group of dogs and their owners before and after a 30-minute interaction. The samples showed that those pets and owners who spent the most time gazing at each other had the biggest surge of oxytocin in their urine. In a second experiment, the researchers sprayed oxytocin into dogs’ noses and found that female dogs stared longer at their owners afterwards. This mutual gazing also increased the owners’ levels of oxytocin.

These results suggest that the affection humans feel for their pet pooches is similar to that felt toward human family members. So, who knows? If oxytocin can help in treating social disorders, perhaps buying the sufferer a big-eyed puppy dog could prove to be as effective as a nasal spray.