The researchers who conducted the study are describing it as a promising breakthrough, saying it could one day help doctors identify people who are more likely to develop the disorder down the track.
Bipolar disorder, was once known as manic depression and is characterised by extreme mood swings, aggression and depression. Around one to two percent of the population suffer the condition and it is associated with an increased risk of suicide.
A study by researchers from the Black Dog Institute and University of NSW and published today in the journal Biological Psychiatry involved conducting MRI brain scans of 47 people aged 18 to 30 who exhibited no symptoms of bipolar disorder but had a close relative with the mental illness.
A control group of 49 similarly-aged people with no family history of bipolar disorder also had their brains scanned.
When shown pictures of people pulling happy, scared or neutral faces, the part of the brain that regulates emotion called the inferior frontal gyrus was less active in the people with a family history of bipolar than those in the control group, the study found.
“It’s a very exciting and interesting result,” said one of the researchers, Dr Philip Mitchell from the UNSW School of Psychiatry.
“While it would not be appropriate to use this test clinically at present to diagnose the risk of bipolar, that’s the path we are heading down,” he said.
“Once we can identify cases at high risk, we can train people at dealing better with stress, being able to recognise and deal with emotions more efficiently.”
Dr Olivia Dean, Alfred Deakin Postdoctoral Research Fellow at Deakin University said the study provided valuable insights into the origins of bipolar disorder.
“Investigating people at risk and in the early stages of illness may provide the best insight into the underlying factors involved in the pathophysiology of bipolar disorder,” she said.
“This study provides valuable information regarding emotional processing in a high-risk group. While the development of biomarkers in psychiatry is in its infancy, there is clearly important advancements, including the current study, that are providing hope to this field.”
Professor Susan Rossell, Professorial Research Fellow at the Brain and Psychological Sciences Research Centre at Swinburne University said brain imaging was used to detect underlying problems that were difficult to observe with behavioural measures of interviewing.
“Emotion regulation is such a fundamental element of bipolar disorder and understanding the processes that are involved is going to be vital in developing new interventions,” she said, describing the new study as very interesting.
“Long term, it will be important to understand what the environmental versus genetic influences are on emotional regulation.”