Differential age-related amygdala response to facial emotions in BD
MedWire News: Children with bipolar disorder (BD) show greater activation of the right amygdala when viewing facial expressions of emotion compared with mentally healthy children and adults with the mood disorder, researchers report.
Writing in the American Journal of Psychiatry, Pilyoung Kim (National Institute of Mental Health, Bethesda, Maryland, USA) and colleagues explain that previous studies have shown that both children and adults with BD exhibit deficits in face-emotion processing and abnormalities in amygdala structure and activity.
"However, to our knowledge, no study has compared bipolar children and adults in amygdala activity during face emotion processing," they add.
To address this, the team recruited 18 children and 17 adults with BD, and 15 mentally healthy children and 22 mentally healthy adults.
There were no significant differences in mean age between pediatric BD patients and pediatric controls, or between adult BD patients and adult controls. There were also no significant between-group differences in gender distribution.
All of the participants underwent functional magnetic resonance imaging of the brain while performing a task in which they were required to view fearful, angry, and neutral facial expressions.
Analysis of the emotion-by-diagnosis interaction revealed that BD patients (children and adults) had greater right amygdala activation in response to fearful expressions than mentally healthy participants. There was no significant difference between BD patients and mentally healthy participants regarding right amygdala activity in response to angry and neutral expressions.
However, analysis of the age group-by-diagnosis interaction revealed that, across expressions, children with BD exhibited greater right amygdala activation than both adults with BD and mentally healthy children, while no difference was observed between adults with BD and mentally healthy adults.
No significant differences were observed regarding left amygdala activation in response to facial expressions among the groups.
"Our study provides the first evidence, to our knowledge, of age-related differences in amygdala activity in response to facial expressions among bipolar patients," comment the researchers.
They conclude: "These findings provide support and guidance for future longitudinal work examining the developmental trajectory of amygdala function, from the asymptomatic risk state through the course of the illness. Knowledge about this trajectory could help in the early detection of bipolar disorder and the development of age-appropriate treatments."
By Mark Cowen