New tool could help diagnose anxiety and improve treatment

Arachnophobia is a common form of anxiety. Photo / Getty Images

A Kiwi researcher aiming to create the world's first biomarker for a psychiatric disorder is appealing for help from those who suffer from anxiety.

Professor Neil McNaughton, of Otago University's Department of Psychology, is trying to transform nearly 50 years of theoretical research into a novel tool that could help clinicians quickly and easily diagnose sufferers of anxiety -- and prescribe the right medication.

Such a leap would be "game-changing" for tackling what remained one of the most common mental disorders in New Zealand: more than 200,000 Kiwis have been diagnosed with a anxiety disorder at some point in their lives.

Over recent decades, McNaughton and his colleagues have developed a detailed theory of how, in certain brain structures, hyperactivity generates abnormal symptoms and "hyper-reactivity" leads to specific clinical syndromes.

Their work has also sought non-invasive ways to measure how so-called "threat-approach" and "behavioural inhibitions" systems were activated in anxiety sufferers.

In a three-year study supported by a million-dollar Health Research Council grant, McNaughton wants to test whether a specially developed biological marker could measure brain reactions of untreated anxiety sufferers that would show that they could be placed into distinct groups and treated accordingly.

"The most important thing I'm interested in asking is, are some patients different from others in a way that doesn't match the standard symptomatic diagnosis that we get these days?"

A biological marker, he said, should be able to predict treatment efficacy better than current symptom-based diagnoses, while boosting treatment results and cost-effectiveness.

The marker would measure an electrical rhythm generated by a particular part of the brain in response to "goal conflict" in a task.

"A doctor could, in principle, use this by fitting an electrode cap on the patient and running them through the test," McNaughton said.

"Unfortunately, at the moment, it is not sensitive enough for diagnosis of a single person and cannot be used for repeat testing."

But it could be used to test effects of drugs in groups of people, and McNaughton and his colleagues hoped to use it as an anchor to develop clinically useful diagnostic tests.

"I'd like to think that, if this works, we'll have the first genuine biomarker for any psychiatric disorder," he said.

"While some people might argue around the edges as to whether there are some already, certainly, for anxiety, this would be pretty much a game changer."

This was because it would provide a "solid biological basis" for giving sufferers a diagnosis that allowed clinicians to determine the best the treatment for them, he said.

"At the moment, a patient will walk in with a whole mass of symptoms. It's always a mess, and if you try one drug, then 30 per cent of the time you may be lucky.

"If we could change that to just checking out the patient with a simple test that tells you what to treat them with, then that would be a major improvement."

It didn't necessarily have to be drugs that the marker indicated as the best treatment option, he said.

"In fact, there are a lot of reasons for supposing anti-anxiety drugs are not particularly good at treating anxiety, but just for holding the symptoms down, kind of like aspirin rather than an antibiotic."

McNaughton is extending the study from Dunedin to other regions, including Auckland, and is keen to hear from people willing to take part.

"We need not only people who have some kind of anxiety disorder, but also those who don't, so we can draw comparisons between them."

*People interested in participating could reach him on anxiety@otago.ac.nz.

ANXIETY IN NEW ZEALAND

&bull: Anxiety disorders are very common among Kiwis. The 2011/2012 New Zealand Health Survey indicated that 6.1 per cent of Kiwis -- or more than 200,000 people -- had been diagnosed with an anxiety disorder at some point. These included generalised anxiety disorder, phobias, post-traumatic stress disorder and obsessive compulsive disorder.

• Rates were highest among women -- 7.7 per cent, compared with 4.4 per cent of men -- and anxiety disorder was particularly high among women aged between 25 and 54.

&bull: According to the Health Loss in New Zealand study, anxiety, along with depressive disorders, were the second leading cause of health loss for New Zealanders, accounting for 5.3 per cent of all health loss, behind only coronary heart disease. For women, they were the leading cause.