'Love Hormone' Oxytocin Shows Promise for Treating Mental Illness

In recent years, we've been bombarded with studies about the hormone oxytocin researchers have demonstrated it increases trust and helps aid in social bonding. It has even garnered a reputation as the "love hormone." But what good is it for? Despite all these findings, the hormone's medical use remains limited to obstetrics it is used to induce labor and aid in breastfeeding.

But researchers are now trying to apply these findings, and are investigating oxytocin as a treatment for psychiatric illnesses. They say its unique ability to adjust our wiring could remedy symptoms of schizophrenia, post-traumatic stress disorder (PTSD) and anxiety, and improve social abilities among those with autism.

A number of oxytocin studies have even reached the stage of clinical trials which test the effectiveness and safety of a substance before it can become an approved drug with promising findings.

"The idea of augmenting ... the way we connect to and with each other, would just be so helpful for so many people," said Dr. Kai MacDonald, an adjunct professor of psychiatry at the University of California, San Diego, who has studied oxytocin as a treatment for schizophrenia.

However, the results so far, while hopeful, have not been "earthshaking," MacDonald said.

There are hurdles to such research. Because oxytocin is a large molecule, it doesn't cross from the bloodstream into the brain very easily. It is also rapidly degraded in both the stomach and the blood.

Also, researchers don't know how big doses need to be, or how frequently it should be given to have a meaningful impact, MacDonald told MyHealthNewsDaily. Figuring out such dosing can be difficult.

Still, "if we could do it with any degree of precision, that would be a lovely therapeutic venue," MacDonald said.

What is oxytocin?

Oxytocin is a hormone released by the pituitary gland that affects both the body and the brain. In the human body, it facilitates contractions of the uterus during labor and helps release milk during breastfeeding.

The hormone affects social interactions in a number of mammals, from mice and moles to dogs and monkeys, MacDonald said. For example, studies have shown that mice given oxytocin will huddle together, and monkeys given the hormone will spend longer grooming each other.

A barrage of studies over the last decade has indicated it has social effects on people as well.

One study found a nasal spray of oxytocin a frequently used way to deliver the hormone, because it provides a direct route to the brain made people more trusting. Participants were more willing to hand over money in an experimental game than those not given the spray.

Other researchers gave men oxytocin and found they more frequently looked to the eye region when shown pictures of human faces. People look to the eyes to read another's emotional state and trustworthiness, MacDonald said. [Related: 11 Interesting Effects of Oxytocin ]

It's not clear that people who take oxytocin feel any different, MacDonald said. It may be that it acts subtly to change behavior or how we process social information, he said.

Though you can buy the hormone on websites that sell what they claim is an oxytocin nasal spray, whether it actually works is a different story. The claims need scientific scrutiny, a process still in its infancy, MacDonald said.

Under investigation

Oxytocin has not been approved to treat any psychiatric disorder, but evidence that it may be effective is building.

A small study published Oct. 1 in the journal Biological Psychiatry found that patients with schizophrenia who took oxytocin for three weeks along with their regular antipsychotic medication improved in their symptoms and hallucinated less than those who took a placebo with their antipsychotic.

While there were only 15 patients and the findings are preliminary, the results suggest oxytocin could treat patients with schizophrenia whose symptoms are not fully alleviated by their antipsychotics, said study researcher David Feifel, also of UCSD.

"The field of treating schizophrenia is kind of at an impasse," Feifel told MyHealthNewsDaily. "All our drugs that we have to date work through the same mechanisms as they did when antipsychotic drugs were first discovered 50 years ago," he said. "We are in desperate need of novel mechanisms that will improve symptoms through a different pathway, and oxytocin clearly is a novel mechanism."

Considering oxytocin's social effects, it makes sense to hypothesize it could treat autism, a condition characterized by having trouble interacting with others. And researchers have shown people with autism naturally have lower levels of oxytocin than those without autism.

A study published in 2007 in Biological Psychiatry found people with autism given oxytocin were able to determine the emotional tone of speech more consistently than those given a placebo.

Studies on other disorders have shown more mixed results. A paper published last year in the journal Psychoneuroendocrinology involving patients with social anxiety disorder found that oxytocin improved participants' self-image when they gave a speech. However, after five weeks of treatment, which also included teaching the patients to confront their social fears, those given oxytocin did no better than patients given the placebo.

Oxytocin is also being tested in clinical trials as a treatment for depression , borderline personality disorder and alcohol withdrawal.

How does oxytocin work?

One hypothesis is that oxytocin dampens the activity of the brain's fear center, the amygdala, thereby easing stress and anxiety.

A decline in anxiety could "allow people to attend to the social cues maybe they normally would avoid," said Jennifer Bartz, a professor of psychiatry at Mount Sinai School of Medicine in New York, who is conducting a clinical trial testing oxytocin as a therapy for autism. There is evidence people with autism experience anxiety in social situations , she said.

Because of oxytocin's proposed blunting effects on the amygdala's activity, scientists have also hypothesized it would help those with PTSD, which is a disorder of fear, said Miranda Olff, head of the Center for Psychological Trauma at the University of Amsterdam in the Netherlands. In PTSD, the brain "still gives the fear response as if people are back in that situation again," she said.

Olff is testing oxytocin's use in patients with PTSD in addition to standard therapies.

"Adding another biological component to this intervention might speed up recovery, or might increase the number of patients that respond to treatment at all," Olff said.

And oxytocin's trust effect could help those with schizophrenia, making them less paranoid, Feifel said.

Scientists don't know how much oxytocin goes into the brain when it is administered as a spray, or whether it even gets there, Feifel said. There is no way to see the hormone in the brain. But the effects it produces such as a reduction in hallucinations would require brain changes, so researchers have reason to believe it reaches the brain, he said.

It's also possible that an oxytocin dose simply triggers the brain to make more of it, MacDonald said.

Future research

While oxytocin's effects so far have been subtle rather than drastic, it could still become an important therapy. MacDonald said that most studies have looked at effects on patients after only a single dose. If Prozac, the widely-prescribed antidepressant, were administered that way, its effects would seem more subtle as well, he said.

The side effects of oxytocin have so far been benign, MacDonald said. But while it's something the body produces naturally, researchers don't know whether upping the body's natural amount, or giving it over long periods of time, could ultimately be harmful.

It also remains to be seen whether oxytocin affects men and women differently. It may present health risks to women because of its role in birth inducing contractions of the uterus. Most studies to date have been conducted in men.

Besides mental disorders, researchers are investigating oxytocin's potential benefit for a number of other ailments, including headaches, constipation and skin damage.

For those who think they might benefit from an oxytocin boost, MacDonald noted that you don't need a spray to prompt the hormone's production."Given that some of the things that are suspected of triggering oxytocin massage, sex, touch, eye contact given that those are uniformly likable, it's hard not to recommend them," he said.

Rachael Rettner

Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.