Wrong impression: bipolar kids misinterpret facial cues as hostile.

Children with bipolar disorder are more likely than other kids to read hostility in bland facial expressions, a new study shows. Misinterpreting social cues might contribute to irritability and the unprovoked aggression that bipolar children sometimes direct toward others, the researchers say.

While the children were misconstruing facial cues, excessive activity arose in brain areas that are associated with emotion processing, magnetic resonance imaging (MRI) revealed. The study is the first to combine tests of facial interpretation and simultaneous MRI measurements in brain regions pivotal to bipolar disorder in children, says study coauthor Ellen Leibenluft, a psychiatrist at the National Institute of Mental Health (NIMH) in Bethesda, Md.

The researchers compared 22 bipolar children with 21 mentally healthy children. Both groups averaged 14 years of age. Eighteen of the bipolar children were taking some form of psychiatric medication.

The participants viewed pictures of people's faces and answered questions about the hostility of each face. The faces were standard representations of anger, fear, happiness, and a neutral mood. The bipolar children rated the first three categories on a par with the other children but read more hostility into the neutral faces than did the others, the researchers report in the June 6 Proceedings of the National Academy of Sciences.

MRI scans of the bipolar children as they rated the neutral face showed revved-up activity in brain regions known to process emotions, particularly in an area called the amygdala, says study coauthor Brendan A. Rich, a child psychologist at NIMH.

Previous research had indicated that bipolar children tend to have smaller amygdalas than other children do, says psychiatrist Melissa R DelBello of the University of Cincinnati. The new research also suggests that the amygdala functions differently in bipolar children, she says.

It's unclear why the amygdala would work overtime while bipolar children read faces, Leibenluft says. It could be because it's undersized or because it communicates poorly with other emotion-processing brain regions, she says.

Because they don't know the cause of bipolar disorder--formerly known as manic depression--scientists can't tell whether difficulties in processing facial cues contribute to manic and depressed states, or whether those mental states hamper the processing of facial cues, Leibenluft says.

At the time of the examination, one-fourth of the bipolar children were slightly manic, one-fourth were mildly depressed, and the rest were neither. Rich notes that facial misconceptions spanned all the bipolar children, regardless of mood.

In daily life, failure to accurately discern intent from facial cues causes problems for bipolar children, DelBello says. "They get irritable with people whom they shouldn't get irritated at. Then, they become hostile and explosive,' he notes.

"Social skills depend on the ability to rapidly infer meaning from facial expression,' Rich says. Children who are slow to do that, or who misconstrue the signals sent to them, may react inappropriately and put off others, he says.

In her practice, DelBello sees evidence that bipolar children also miss some cues altogether. "There are kids who are very disruptive in the classroom" she says. "They can't put the brakes on because they can't read that the teacher is upset."

By paying attention to this inability to grasp facial signals, therapists might diagnose bipolar disorder earlier and teach children to better recognize cues to other people's emotions, Leibenluft says.