Bipolar children have greater activation in the right amygdala -- a brain region important for emotional reaction -- than bipolar adults when viewing emotional faces, according to a new study.  

The research, published in JAMA Psychiatry in the US, claims bipolar children might benefit from treatments that target emotional face identification, such as computer based "brain games" or group and individual therapy.

This study is the first ever meta-analysis to compare brain changes in bipolar children to bipolar adults, using data from 100 functional MRI (fMRI) brain imaging studies with a pool of thousands of participants.

Dr Ezra Wegbreit, a research fellow at Bradley Hospital in Rhode Island, led the study: "Bipolar disorder is among the most debilitating psychiatric illnesses affecting adults worldwide, with an estimated prevalence of one to four percent of the adult population, but more than 40 percent of adults report their bipolar disorder started in childhood rather than adulthood.

"Despite this, very few studies have examined whether brain or behavioral changes exist that are specific to children with bipolar disorder versus adults with bipolar disorder."

While fMRI studies have begun to investigate the neural mechanisms underlying bipolar disorder, few have directly compared differences in youths with bipolar disorder and bipolar adults. To address this gap, the research team conducted the large scale meta-analyses, directly comparing fMRI findings in bipolar youths versus bipolar adults, both relative to non-bipolar participants.

Analysis of emotional face recognition fMRI studies showed significantly greater amygdala activity among bipolar youths than bipolar adults. The team also analysed studies using emotional stimuli, which again showed significantly greater levels of brain activation in bipolar children, this time in the inferior frontal gyrus and precuneus areas of the brain.

In contrast, analyses of fMRI studies using non-emotional cognitive tasks showed a significant lack of brain activation in the anterior cingulate cortex of bipolar children.

"Our meta-analysis has located different regions of the brain that are either hyper active or under active in children with bipolar disorder," said Wegbreit. "These point us to the targeted areas of the brain that relate to emotional dysfunction and cognitive deficits for children with bipolar disorder."