Relation Between Brain Morphological Features and Psychiatric Hospitalization Risk in Major Depressive and Bipolar Disorders

Abstract

Introduction: Patients with mood disorders, especially, major depressive disorder (MDD) and bipolar disorder (BD), are at heightened risk of relapse and psychiatric rehospitalizations. Therefore, there is an urgent need to identify modifiable biomarkers to inform personalized and intensified prevention strategies for those at the greatest risk of relapse and hospital readmissions. Brain structural measures subserving cognitive function hold particular promise among potential predictive biomarkers. Methods: In the present study, structural magnetic resonance imaging scans were obtained from 319 patients with BD (n = 241) or MDD (n = 78). [Correction added on 7 March 2025, after first online publication: In the preceding sentence, ‘MDD (n=241) or BD (n=78)’ has been changed to ‘BD (n=241) or MDD (n=78)’.] Longitudinal data on psychiatric hospitalization for up to 10 years were available from the Danish National population-based registers. Interhemispheric hippocampal asymmetry, a putative marker of cognitive function and brain reserve, was calculated for each patient. The association between hippocampal asymmetry and future psychiatric hospitalization was assessed using a cause-specific Cox regression model. Exploratory analyses, also using a cause-specific Cox model, assessed the association of prefrontal and hippocampal gray matter volume and whole-brain white matter volume with hospitalizations. Results: The results indicated a negative association between rightward hippocampal asymmetry (i.e., left