NARRATION

Ah, weddings - the ultimate celebration of romantic love for many. That magical chemistry between husband and wife is tied up with the molecule oxytocin. It's dubbed 'the love hormone'.

Dr Graham Phillips

But oxytocin is responsible for a lot more than just love. New science has shown this amazing molecule also influences how sociable each of us is. Kind of allows us to tune in to the social information around us, allowing us to perceive it in much higher resolution.

Professor Larry Young

Oxytocin is intrinsically pro-social. It's simply making your brain pay attention to social information around you.

Dr Graham Phillips

The oxytocin system develops during childhood, and it now seems, if that system doesn't develop properly, you're more prone to alcoholism and drug addiction as an adult.

NARRATION

Scientists are now discovering oxytocin's potential to treat a range of social disorders, like drug addiction.

Professor Iain McGregor

I think there's something a wee bit special about oxytocin itself and harnessing its power could actually be a game changer.

NARRATION

In recent years, laboratories around the world have been unravelling the complexity behind oxytocin. It's the molecule of the moment.

Dr Graham Phillips

Femke.

Dr Femke Buisman-Pijlman

Hi, Graham.

Dr Graham Phillips

I'm ready for testing.

NARRATION

Femke's lab here in Adelaide is one of them. Despite the promise of this exciting chemical, testing for it is still, mm, pretty crude.

Hannah

Just a passive drool will be fine. Don't spit.

Dr Graham Phillips

What is the polite way...? Don't spit.

Hannah

No big spits. Drool it over your lip.

Dr Graham Phillips

Passive drool, I know.

NARRATION

We now know oxytocin is found in both men and women.

Dr Graham Phillips

That's about as passive as it gets.

Hannah

Perfect. Thank you.

NARRATION

But when it was first discovered early last century, it was thought to be a purely maternal hormone. Circulating in the blood stream, it stimulates uterine contractions and it controls the let-down reflex for breast milk. But oxytocin is also at work in the brain as a neuropeptide, encouraging bonding.

Professor Iain McGregor

Nature has been very clever in a way. Without oxytocin, you know, babies are what they really are - I probably shouldn't say this on TV - but noisy, smelly animals that don't actually do anything useful. And, um, that's what oxytocin does. It gives them a special salience, a special beauty and allows us to bond with these defenceless little animals.

NARRATION

Another little animal, the vole, has shown that oxytocin also plays a key role in partner bonding.

Professor Larry Young

Because of the work that we've done here on prairie voles, where we show that oxytocin does indeed cause two prairie voles to form a bond, or maybe fall in love.

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Surprisingly only 5% of mammals are monogamous, and this particular vole, the prairie vole, is one of them.

Professor Larry Young

After mating, these two animals want to spend the rest of their life together. And we can bring them into the laboratory and we can see this transformation happening. Other kinds of voles that look exactly the same are pretty much asocial, they will have sex, they'll mate, but that bond does not form.

NARRATION

The reason for the difference is the density of oxytocin receptors in the brain. Life pair bonders, like prairie voles or, indeed, ourselves, have a high density of receptors in the reward centre of the brain. Non-pair bonders, like meadow voles, certainly enjoy sex, but their lower density of receptors means it doesn't matter so much who the partner is. So it's not the oxytocin itself making sex enjoyable. What it's doing is influencing our mating behaviour.

Professor Larry Young

What would arise now is that oxytocin is just one molecule in a chemical cocktail that, indeed, does help animals fall in love and form bonds. But the specific role that oxytocin has is really in focussing the attention on the social cues.

NARRATION

Which means oxytocin is facilitating social connection on a much broader scale.

Professor Larry Young

Oxytocin's role in relationships goes well beyond the mother-infant or romantic partnership. It really is in all kinds of relationships.

Dr Femke Buisman-Pijlman

We know that oxytocin, when we release it ourselves, for example, when we have social contact, can make us feel an enjoyment like a drug would, but a little bit less, but a very positive rewarding feeling. But you have to learn to be able to do that. So if you haven't had early positive social experiences, you won't learn to really enjoy that.

NARRATION

We're all born with the foundations of an oxytocin system in our brains. But for it to function effectively, it needs to be primed.

Dr Graham Phillips

Evie, why don't you put the white dress on her? I think that will look good. It's in the first few years of life, through eye contact and touch, that the oxytocin system develops in both the brain and body. Ah, that looks fantastic! That's perfect!

NARRATION

How well the system develops depends on what we experience.

NARRATION

From very early on, social stimulation, like touch and eye contact, is crucial for development.

Dr Femke Buisman-Pijlman

In these interactions, it really sets the child up to expect warmth and a secure base to come back, even if they go exploring.

NARRATION

Femke is currently studying the oxytocin levels in mothers and their babies.

Dr Femke Buisman-Pijlman

We're trying to link what we see in mother-child interaction to their oxytocin levels before and after a short interaction.

Emily

Ready?

Baby

(Cries)

Emily

It's alright.

NARRATION

I can see she's not going to passively drool. My oxytocin levels are also being tested to see how they change when I hang out with my daughters.

Dr Femke Buisman-Pijlman

Our research mainly focusses on this early social experiences that people have that can be positive or negative, and that can really shape our developing brain. There have been some very interesting studies, for example, with children that grew up in Romanian orphanages. And we know that that early start, where it's really deprived from social contact and physical contact, had a massive impact. So we see that oxytocin levels, for example, are much lower than we would expect in other kids.

NARRATION

This area of social neuroscience is very young, but the emerging theory is, without a properly primed oxytocin system, the brain is less likely to get reward out of social connections.

Dr Graham Phillips

So where's the reward system of the brain?

Professor Iain McGregor

We think that the most important region is the nucleus accumbens, which is kind of up here. The nucleus accumbens is where we can measure a release of the neurotransmitter dopamine when humans or animals take drugs or are exposed to other rewarding stimuli, such as sex. Or gambling, for example, or monetary reward activates the nucleus accumbens as well.

NARRATION

And according to Iain, there may not be just one reward system.

Professor Iain McGregor

I've pondered whether maybe there's two parallel reward systems in the brain, you know, one for social reward that involves other human beings, and one for what you might call object-orientated rewards.

NARRATION

Loving an object, like a new phone, or objects like drugs or alcohol. So, give an alcoholic oxytocin and they might lose their love of alcohol.

Professor Iain McGregor

Oxytocin maybe just flicks that switch from object-orientated reward towards social rewards.

NARRATION

To test the theory, laboratory rodents were given open access to alcohol. But first, some were given oxytocin.

Dr Michael Bowen

We took a group of adolescent rats and we gave half of them oxytocin pretreatment very early on in their development and the other half we gave just placebo or saline injections.

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The results were striking.

Dr Michael Bowen

The rats that had been treated with oxytocin during early adolescence grew up to develop lower levels of alcohol consumption, they were more sociable and they were less anxious.

NARRATION

The work was extended to giving young rats methamphetamine and they found similar results.

Dr Graham Phillips

That's potentially inoculation for drug addiction.

Professor Iain McGregor

Exactly right. And it's not just inoculation against drug addiction, you can also detect that with this early life exposure to oxytocin, they grow up less anxious as well and they grow up more sociable as well. So there's this enduring change in state that we see with oxytocin that can last way beyond exposure.

NARRATION

While delving into the mechanism behind oxytocin's protective effect, Michael Bowen made an extraordinary discovery.

Dr Michael Bowen

What we noticed was that all the rats that had received oxytocin straight into their brain immediately prior to being given alcohol, were up and moving about and seemed to be completely sober. Whereas all of the rats that had just been given the alcohol were, as we would predict from the dose that we were giving them, quite drunk. And so we thought, 'Wow, what's going on here?' It was almost as though the oxytocin was blocking the intoxicating effects of the alcohol.

NARRATION

In other words, Michael had stumbled on a drug that prevents drunkenness. And they could clearly demonstrate it in the lab.

Dr Graham Phillips

This is a sobriety test for mice. Basically, they have to stay on that cylinder as it spins. Easy to do when you're sober, really hard to do when you're drunk, because alcohol affects the brain's cerebellum, which plays a crucial role in coordinating... movement. One's gone already, I think.

NARRATION

But the drunk mice which were also on oxytocin could stay on the cylinder. The explanation for oxytocin's sobering effect is found in the nucleus accumbens, that key area in the brain's reward system.

Dr Michael Bowen

What we found is that oxytocin, when we administer it straight into the brain of rats, is actually preventing alcohol from stimulating dopamine release in the nucleus accumbens. When you look at all addictive substances, be it alcohol, cocaine, methamphetamine, heroin, they all stimulate dopamine release in this part of the brain.

NARRATION

But Michael's keen to point out that oxytocin won't lower blood alcohol levels.

Dr Michael Bowen

It's not doing anything to your ability to process the alcohol. So it's not a case that it's making you process the alcohol much more quickly, so it's getting out of your system more quickly. Your blood alcohol level is going to be exactly the same.

NARRATION

It's alcohol that's been a major problem in Rachael Laidler's life. She began drinking heavily at 18. By 21, she was on two-thirds of a bottle of scotch a night.

Rachael Laidler

I had built up such a tolerance at that time and it didn't have the same effect on me as it did a year ago. So it was more looking at my lifestyle and about the consequences in the rest of my life.

NARRATION

Two years ago, Rachael managed to stop drinking. But statistics show, and any recovering addict will tell you, one of the hardest parts of recovery is staying sober. Something Rachael knows only too well.

Rachael Laidler

About three months after quitting, I did have a major relapse, which was falling back into old habits for about two weeks. And the whole time I knew what was happening, I knew how dangerous it was, but I couldn't stop myself. I felt like I couldn't connect to anyone without drinking. I couldn't talk to my friends, I couldn't be open and honest with anybody in my life without already having had a few drinks. It was a really disconnected, really unpleasant feeling. That's what I couldn't sit with and I couldn't cope with that feeling, so I went back to drinking.

NARRATION

Treating feelings of disconnection is where oxytocin shows particular promise. Current ways of treating withdrawal and relapse for many drugs of abuse are limited.

Professor Iain McGregor

We're desperate for some kind of intervention to help people who have these addictions. So the preclinical science, the science with rats, is one of the few ways we can identify novel treatments that may be effective in the clinic.

NARRATION

This study at Macquarie University has been investigating one such treatment. They've been looking at oxytocin's potential to reduce relapse in methamphetamine addiction. Rats with a jugular catheter press a lever to self-administer methamphetamine. It's delivered straight into their blood streams.

Associate Professor Jennifer Cornish

So if we give a pretreatment of oxytocin just before the self-administration session, the animals won't work as hard to consume methamphetamine and we show that the drug-seeking behaviour is really reduced. It's quite a striking effect, actually.

NARRATION

Although full human clinical trials are still to be done, the results of a small Sydney study of alcohol-dependent men are certainly encouraging.

Associate Professor Adam Guastella

This is the, er, oxytocin placebo spray.

NARRATION

Over a period of four weeks, the 33 participants were given either oxytocin as a nasal spray or a placebo.

Associate Professor Adam Guastella

At the one-month follow-up, so when they hadn't been taking the drug for a month and there'd been a period of no intervention, the placebo group had relapsed back into drinking at baseline levels. In contrast, the oxytocin group maintained the abstinence of drinking.

Dr Graham Phillips

Really? That's a pretty exciting result.

Associate Professor Adam Guastella

Oh, look, we're thrilled with the result as a proof-of-concept preliminary study.

NARRATION

Given all of oxytocin's positive associations and its availability on the internet, it's tempting to wonder why we don't all get some.

Professor Iain McGregor

If you were to go on the internet, read the hype, you'd probably think it'll be something like having an ecstasy tablet or having an orgasm or something like that, but the reality is you probably wouldn't be able to distinguish it from placebo. So the effects are extremely subtle. Now, that subtlety isn't necessarily because of oxytocin itself being a subtle hormone, it's just this issue of it penetrating the brain. So when you take it intranasally, we're still trying to work out how much gets into the brain, but probably only a vanishingly small amount.

NARRATION

That's why Iain and other pharmaceutical scientists are focussed on developing better methods for delivering oxytocin into the brain.

Professor Larry Young

For example, when a mother is nursing her baby, that stimulation from the breast is going into the brain and causing those oxytocin neurons to fire and release oxytocin directly into the brain. That's much more powerful than what happens with a nasal spray. So I think that, you know, in the future, we may have these drugs that can, in a very potent way, tap into this oxytocin system to treat many different kinds of disorders.

NARRATION

There's certainly great potential for therapeutic oxytocin. But considering the complexity of human behavioural problems, it's likely any pharmaceutical intervention would only form part of a suite of treatments. So what about my oxytocin results? Does spending time with my daughters have an effect?

Dr Femke Buisman-Pijlman

I've got your oxytocin levels here.

Dr Graham Phillips

Yeah.

Dr Femke Buisman-Pijlman

This is before and after watching TV with your kids. And what do you see?

Dr Graham Phillips

With my kids, they've actually gone up quite significantly.

Dr Femke Buisman-Pijlman

Yeah, they almost doubled.

Dr Graham Phillips

So why is that?

Dr Femke Buisman-Pijlman

Well, we know that when you're in close contact with your kids and you feel quite protective about them, you get a nice oxytocin increase.

Dr Graham Phillips

So, we were sitting on the couch arm in arm almost.

Dr Femke Buisman-Pijlman

Yeah, exactly. Well, that physical contact is really important to get an increase in oxytocin.

Dr Graham Phillips

See you, beautiful.

Bri

Bye.

Professor Iain McGregor

The inference is, I think, from our animal work, that if you're the parent of a teenage person, particularly 12, 13, 14, 15, even though they may not like it, make sure to give them lots of hugs, because that love that you transmit to your children may well inoculate them against a career of drug addiction and misery.

Liv

Bye.

Dr Graham Phillips

See ya.