Amygdala Volume Differences in Autism Spectrum Disorder Are Related to Anxiety.

Recent studies suggest that longstanding findings of abnormal amygdala morphology in ASD may be related to symptoms of anxiety. To test this hypothesis, fifty-three children with ASD (mean age = 11.9) underwent structural MRI and were divided into subgroups to compare those with at least one anxiety disorder diagnosis (n = 29) to those without (n = 24) and to a typically developing control group (TDC; n = 37). Groups were matched on age and intellectual level. The ASD and anxiety group showed decreased right amygdala volume (controlled for total brain volume) relative to ASD without anxiety (p = .04) and TDCs (p = .068). Results suggest that youth with ASD and co-occurring anxiety have a distinct neurodevelopmental trajectory.