Exploratory analysis of the relationships of sleep disorders, emotional symptoms and blood inflammatory markers with suicidal ideation in major depressive disorder.
BACKGROUND Suicidal ideation (SI) represents a severe consequence of major depressive disorder (MDD). While sleep disorders and immune dysregulation are associated with SI, the precise associations and complex mediating pathways involving sleep disturbances, inflammatory biomarkers, and anxiety and depression severity remain poorly understood. METHODS A total of 157 patients suffering from MDD were enrolled. Based on Item 3 of the 17-item Hamilton Depression Rating Scale (HAMD), participants were categorized into SI and non-suicidal ideation (NSI) groups. Sleep disorders were assessed using the Pittsburgh Sleep Quality Index (PSQI). Peripheral inflammatory markers were from complete blood counts. Spearman correlation analysis and multiple logistic regression methods were employed to analyze the associations of sleep disorders, emotional symptoms, and inflammatory markers with SI. Additionally, a bidirectional mediation analysis was conducted to explore the association of these variables with SI. RESULTS Patients with SI exhibited poorer sleep quality and altered inflammatory profiles. Significant correlations were observed among affective symptoms, sleep measures, and immune markers. The results showed that in models excluding emotional symptoms, the global PSQI score and sleep disturbances component were associated with SI. Mediation analysis indicates that the percentage of lymphocytes was indirectly associated with SI via the sleep disturbances and daytime dysfunction components. The daytime dysfunction component and HAMA score were associated with SI through bidirectional mediating pathways. CONCLUSIONS Sleep disorders, inflammatory dysregulation, and anxiety symptoms constitute an interconnected network associated with SI in MDD. These findings highlight the importance of comprehensive, integrated interventions.