Decreased brain connectivity linked to bipolar risk

Researchers have for the first time discovered that crucial brain networks show signs of reduced connectivity in at-risk individuals prior to the development of bipolar disorder.

Tamara and Brydie Tancred grew up at high risk of bipolar disorder but have avoided the disease. Picture: Jane Dempster

Researchers have for the first time discovered that crucial brain networks show signs of reduced connectivity in at-risk individuals prior to the development of bipolar disorder.

A brain imaging study conducted by scientists from the University of NSW, the Hunter Medical Research Institute and the University of Newcastle, together with international institutions, revealed brain networks involved in emotional processing and thinking diminished over time after the onset of adolescence in those with a family history of bipolar disorder.

Researchers scanned the brains of 97 young people with high genetic risk of developing bipolar disorder two years apart and compared their scans with those not at risk. They found there was a decrease in connectivity between regions of the brain devoted to emotional processing and cognition between the two scans in at-risk individuals.

However, in those who had no genetic risk factors, there was a strengthening of neural connections between these same regions.

Scientia professor Philip Mitchell, a physician and academic psychiatrist with UNSW Medicine & Health, said the major pathway that showed signs of reduced connectivity in at-risk individuals was involved in mood regulation.

Bipolar disorder is characterised by dramatic and contrasting swings of mood between a manic state and depression.

“The major issue this study has identified is that even before the illness is becoming obvious, there are changes in these critical brain networks already occurring,” Professor Mitchell said.

“It means that it just heightens the importance of getting in early and identifying changes so that you can stop or at least attenuate the impact of illness.”

He said the study laid the groundwork for the development of early intervention strategies that may prevent bipolar developing in at-risk individuals.

That would involve programs aimed at building resilience, the management of anxiety and depression, and the avoidance of drugs and alcohol.

Sisters Tamara and Brydie Tancred, 31 and 28, were at high risk of developing bipolar disorder as their father is a sufferer.

The pair were aware of the need to manage their risks. They believe that having a supportive family environment and avoiding drugs and alcohol as teenagers have been contributing factors in remaining free of the illness.

“(With) my father and my uncle both being diagnosed, there was always a possibility it might come about for me or my sister,” Tamara says. “You can never truly avoid it but there are steps you can take to try to mitigate it.”

Brydie says the risk of developing the disorder always played on her mind.

“We had conversations from a really young age with my dad,” Brydie says. “I guess his generation didn’t have as much understanding of the fact that taking drugs or drinking a lot of alcohol can have links with mental health.

“That’s something that me and my sister have always wanted to avoid.”