Mediation model of comorbid anxiety disorders in late-life depression

BACKGROUND: A number of studies have been conducted on risk factors of comorbid anxiety disorders regarding late-life depression (LLD). This study investigated the associated factors and their relationship to comorbid anxiety disorders in LLD. METHODS: Participants included 190 elderly Thais (73.2% female, with a mean age of 68.39 ± 6.74 years) with depressive disorders, diagnosed according to DSM-IV Diagnosis Axis I disorders assessed by Mini-International Neuropsychiatric Interview. Demographic data, medical and psychiatric history, family psychiatric history, past depression, family history of depression, Neuroticism Inventory and 7-Item Hamilton Depression Rating Scale (HAMD-7) were analyzed for path analysis using Structural Equation Model framework. The bootstrapping method was used for testing indirect effects. RESULTS: Being female was associated with comorbid anxiety disorders with an indirect effect (β = − 0.032, P = 0.018) through neuroticism, depression severity, history and family history of depression. Family history of depression had no effect on comorbidity (P = 0.090). Neuroticism had an indirect effect on comorbid anxiety disorders (β = 0.075, P = 0.019) via depression severity as reflected by HAMD-7 score (β = 0.412, P = < 0.001). Total variance explained from this model was 11%. This model had good-fit index with Chi-square > 0.05, CFI and TLI > 0.95 and RMSEA < 0.06. CONCLUSION: Neuroticism mediates the effect of relationship between sex, family history and history of depressive disorders and comorbid anxiety disorders in LLD. Moreover, depression severity is a mediator for neuroticism and comorbid anxiety disorders. Longitudinal studies are warranted to indicate the importance of effective treatment of depression to lower the risk of developing comorbid anxiety disorders among depressed elderly.