The average two to three years it currently takes for an individual to find a depression medication that works for them, could instead be determined in a matter of weeks with the help of a brain scan.
About a million people per year are diagnosed with depression in Australia, and with that comes one of the highest rates of antidepressant use in the world — with more than one in 10 Australians using them.
‘Only 30% of patients respond to anti-depressants in the first choice of medication while the remaining two-thirds take about a year or two.’
Professor Philip Mitchell, from the school of Psychiatry at the University of NSW and a research fellow at the Black Dog Institute, said while 30 percent of people will have a full response to their first choice of medication, that leaves two thirds who do not.
"People do find that difficult and I think that can be demoralising, particularly if people are significantly depressed," he said.
The study, published in the American journal Proceedings of the National Academies of Sciences, used two measures:
First, they asked depressed patients to answer a questionnaire about their exposure to early life stress.
Then, an MRI machine measured particular brain reactions while the patients were shown pictures of different facial expressions.
They wanted to see how the amygdala — which is the part of the brain which generates emotions — would react.
Dr Mayuresh Korgaonkar, from the Westmead Institute for Medical Research and one of the authors of the report, said they showed the patients happy faces and studied their reactions.
While some of the patients reacted normally, and others had a low reactivity —signifying that they had an impaired amygdala.
"And what we found was that information was actually linked to how they would respond to antidepressants," he said.
"Where those who had normal or preserved a reactivity to happy faces, they were the ones who actually responded to antidepressants."
Dr Korgaonkar said the reason for this outcome came down to how a patients amygdala was impaired.
"In a patient who are more vulnerable for depression — in other words early life stress has actually impaired their amygdala — and hence the reactivity to those happy faces are the ones who are not responding to antidepressants."
Professor Mitchell said while the finding was an exciting one, they needed other groups around the world to come up with similar findings before they could have strong confidence in their own.
"But I think it points the way to how we'll be understanding and treating mental illness in the future," he said.
"That as well as good clinical assessment, we'll be able to use tools like sophisticated brain imaging to be able to help us in these decisions of who will respond, and who won't to medications like antidepressants."