Amygdala Volumes in Autism Spectrum Disorders: Meta-analysis of Magnetic Resonance Imaging Studies

We conducted meta-analysis in order to determine if there are significant differences in left and right amygdala volume in individuals with autism spectrum disorders (ASD) compared to a control group. Twenty-three studies fulfilled inclusion criteria for our study. Right amygdala volume was significantly larger in ASD patients compared to controls (Hedges’ g 0.44; 95% CI 0.04–0.83; Z = 2.26; p = 0.024), while there was no significant difference in left amygdala volume between ASD patients and controls (Hedges’ g 0.44; 95% CI − 0.10–0.98; Z = 1.67; p = 0.095). However, between-study heterogeneity was significant so there is an unequivocal need for new uniform magnetic resonance imaging (MRI) studies to get a more precise answer to the question of whether there is a difference in amygdala volume between ASD patients and controls.