Insights into bipolar disorder: Young patients misread emotional cues

A new study provides some of the first clues to the underlying workings of episodes of bipolar disorder that disrupt friendships, school, and family life in as many as 1% of children. Children and adolescents with bipolar disorder misread facial expressions as hostile and show heightened neural reactions when they focus on emotional aspects of neutral faces, researchers at the National Institutes of Health's (NIH) National Institute of Mental Health (NIMH) have discovered.

Brain scans showed that the left amygdala, a fear hub, and related structures became activated more in youth with the disorder than in healthy youth when both groups were asked to rate the hostility of an emotionally neutral face, as opposed to a non-emotional feature, such as nose width. The more patients misinterpreted the faces as hostile, the more their amygdala flared.

Such a face-processing deficit could help account for the poor social skills, aggression, and irritability that characterizes the disorder in children, suggest Drs. Ellen Leibenluft, Brendan Rich, Daniel Pine, NIMH Mood and Anxiety Disorders Program, and colleagues, who reported on their findings in May in the Proceedings of the National Academy of Sciences.

Magnetic resonance imaging (MRI) studies have shown that, unlike in adults with the illness, the amygdala is consistently smaller in bipolar children than in healthy age-mates. Also, the NIMH researchers had found earlier that bipolar children falter at identifying facial emotion and have difficulty regulating their attention when frustrated.

Using functional MRI, the researchers measured brain activity in 22 bipolar youth and 21 healthy subjects while they rated faces. In addition to the amygdala, other parts of the emotion-regulating circuit—nucleus accumbens, putamen, and left prefrontal cortex—were also hyperactive in patients, compared to healthy peers, during the emotional tasks. Patients rated themselves as more afraid, and they rated the faces as more hostile, compared to healthy peers. The groups did not differ on nose width ratings-confirming that differences were specific to perceiving emotional processes.