Excess mortality in depressive and anxiety disorders: The Lifelines Cohort Study

Background
To examine the mortality risk of current and life-time depressive as well as anxiety disorders, whether this risk is moderated by sex or age, and whether this risk can be explained by lifestyle and/or somatic health status.

Methods
A cohort study (Lifelines) including 141,377 participants (18–93 years) which were followed-up regarding mortality for 8.6 years (range 3.0–13.7). Baseline depressive and anxiety disorders according to Diagnostic and Statistical Manual of Mental Disorders, fourth edition criteria were assessed with the Mini International Neuropsychiatric Interview and lifetime diagnoses by self-report. All-cause mortality was retrieved from Statistics Netherlands. Cox-regression was applied to calculate proportional hazard ratios, adjusted for lifestyle (physical activity, alcohol use, smoking, and body mass index) and somatic health status (multimorbidity and frailty) in different models.

Results
The mortality rate of depressive and anxiety disorders was conditional upon age but not on sex. Only in people below 60 years, current depressive and anxiety disorders were associated with mortality. Only depressive disorder and panic disorder independently predicted mortality when all mental disorders were included simultaneously in one overall model (hazard ratio [HR] = 2.18 [95% confidence intervals (CI): 1.56–3.05], p < 0.001 and HR = 2.39 [95% CI: 1.15–4.98], p = 0.020). Life-time depressive and anxiety disorders, however, were independent of each other associated with mortality. Associations hardly changed when adjusted for lifestyle characteristics but decreased substantially when adjusted for somatic health status (in particular physical frailty).

Conclusions
In particular, depressive disorder is associated with excess mortality in people below 60 years, independent of their lifestyle. This effect seems partly explained by multimorbidity and frailty, which suggest that chronic disease management of depression-associated somatic morbidity needs to be (further) improved.