Ella McLeod and Dr Olivia Harrison with the breathing equipment for their research at the University of Otago. Photo: Claire Concannon / RNZ
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We all experience anxiety from time to time. Being able to think about future threats is a really useful faculty of the human brain.
But sometimes, it takes things just a bit too far.
When our brains are overcome with constant negative thoughts about what may or may not happen it can result in intense physical symptoms.
Anxiety becomes disordered when it stops people from going about their everyday activities. An estimated one in four New Zealanders will experience anxiety disorder across their lifetime, and levels of anxiety, especially in young people, are rising.
Interoception - the brain-body connection
At the core of anxiety is the brain-body connection. Our thoughts trigger the fight or flight response that affects our physiological systems, holding the body in a tense, ready to go state.
But if we are anxious are we are more, or less, aware of how our body is reacting? And do treatments for anxiety alter this awareness?
Taking in information from one of our fives senses, like vision for example, and making sense of that in the brain, is known as exteroception.
The perception of signals from within our own body is called interoception. Think about signals from your gut, your bladder, or breathing or heart rate changes. It's a relatively new field for science because it's difficult to safely alter an internal signal and measure someone's perception to it.
But Dr Olivia (Liv) Harrison, senior lecturer of neuroscience and psychology at the University of Otago, has figured out a way to do it.
Breathing as a tool to study brain-body perception
While some people can perceive their heartbeat it's not a universal signal everyone can tune in to. But we all have both subconscious and conscious control over our breathing.
Liv and her colleagues have devised an experiment where a participant's breathing effort can be altered by narrowing the tube they have to breathe through. They then ask them about whether they can perceive a change or not, and how confident they are in their answer. This allows them to gauge both their confidence and also their insight - are they right to be confident?
By using this experimental test, they were able to show that those with moderate anxiety were less perceptive to breathing changes than those with low anxiety levels.
Now they are using this test to investigate different potential treatments for anxiety, to find out whether they alter this interoception ability.
Investigating across the spectrum of anxiety
Liv and her team, including recent Master's graduate Ella McLeod, are currently running a number of experiments that are investigating across the spectrum from low, to moderate, to disordered levels of anxiety.
On the clinical end of the spectrum, they are running a longitudinal study with people who have been given medication.
In New Zealand, those with high levels of anxiety are often prescribed SSRIs - selective serotonin reuptake inhibitors. These drugs were originally designed to treat depression but are also effective for many anxiety disorders.
Ella, Liv and the team have been testing participants before, or at the start of their SSRI treatment, and again after six weeks. Their preliminary results are striking - the SSRIs are increasing the sensitivity of the patients to changes in their breathing, but they are not affecting the confidence or insight of the participants.
Liv says it is about understanding what SSRIs can and can't do. "Really what we are seeing is it [treatment with SSRI] creates a window. So, you improve that sensitivity to both body perceptions and the perceptions of the world around us because we've decreased that overall fight-flight response… and that means that that person is now potentially in a state that they could do other things. So, we could intervene with behavioural therapies, we could intervene with cognitive talk therapies, or other things that can really help social anxiety."
Study participant Patrick Mazzocco. Photo: Claire Concannon / RNZ
Stop looking for the one thing
The internet is full of videos claiming that they have discovered the 'one thing' to quiet or cure anxiety, but this is part of the problem, says Liv.
"There's a bit of a misnomer that there's just one answer, and by perpetuating that we set people up to fail."
Patrick Mazzocco is taking part in another study in the lab investigating the effects of exercise on the interoception perception of people with moderate anxiety. What helps him is going for a walk outside, but also talking it through with a trusted friend.
"Just having someone outside of my own head to help put it into perspective".
What works will be the thing that that person enjoys and will do, says Liv. She is hoping their research will help answer some of the questions clinicians have so they can better target treatment to different people at this particularly crucial time of rising anxiety levels.
"What happens is, in evolution, is that things change quickly, and we have to adapt as a species. And we are really at that change point, we've seen so much change over the last few decades and we're still adapting. So that's where we really see those prevalence increases like we have at the moment."