A case report on the role of amygdala anatomy in psychiatric disorders

Abstract

The amygdala is a key structure within the medial temporal lobe involved in emotional processing, fear responses, social behaviour, and stress regulation, and growing evidence suggests that structural and functional alterations of the amygdala contribute to several psychiatric disorders. This case report and systematic review with meta-analysis examined the relationship between amygdala anatomy and psychiatric disorders, with particular attention to trauma-related dissociative symptoms. A 43-year-old Asian female was admitted to an inpatient psychiatric unit with suicidal ideation and recurrent dissociative episodes characterized by unresponsiveness, loss of control, and out-of-body experiences in the context of repeated childhood sexual trauma; electroencephalography, computed tomography of the head, and routine laboratory investigations were within normal limits. A systematic literature search of PubMed/MEDLINE, PsycINFO, Google Scholar, Web of Science, and the Cochrane Library was conducted for studies published between 2000 and 2025 examining amygdala volume, structure, connectivity, or functional activity in adults with psychiatric disorders compared with healthy controls. Twenty-five studies comprising 1,847 patients and 1,562 healthy controls were included in the meta-analysis using random-effects models and Hedges' g. Significant reductions in amygdala volume were reported in antisocial personality disorder (g=-0.64, 95% CI: -0.82 to -0.46, p<0.001), dissociative disorders (g=-0.42, 95% CI: -0.67 to -0.17, p=0.001), and substance use disorders (g=-0.35, 95% CI: -0.58 to -0.12, p=0.003), whereas increased amygdala volume was reported in post-traumatic stress disorder (g=0.48, 95% CI: 0.29-0.67, p<0.001) and anxiety disorders (g=0.39, 95% CI: 0.21-0.57, p<0.001). Heterogeneity ranged from moderate to high, with I² values of 58-76%, and trauma history significantly moderated amygdala volume effects. These findings support an association between psychiatric disorders and disorder-specific alterations in amygdala structure and function, while the presented case illustrates the possible clinical relevance of trauma-related amygdala dysregulation in dissociative symptomatology. Further longitudinal and multimodal neuroimaging studies are required to clarify causal mechanisms and determine the clinical utility of amygdala-based biomarkers.