Depression is reported to increase general mortality. For cause-specific mortality, there is evidence for the effect of depression on cardiac mortality and suicide. Less is known as to other mortality diagnoses. The literature on anxiety in relation to mortality is scarce and conflicting. This study investigates empirically the association between anxiety/depression and cause-specific mortality with particular attention to underlying mechanisms and causes of death.

Employing a historical cohort design we utilized a unique link between a large epidemiological cohort study and a comprehensive national mortality database. Baseline information on physical and mental health (HADS) was gathered from the population based health study (N=61349). Causes of death were registered with ICD-10 diagnoses during 4.4 year follow-up.

Case-level depression increased mortality for all major disease-related causes of death, whereas case-level anxiety and comorbid anxiety/depression did not. The effect of depression was equal in cardiac mortality compared to all other causes combined, and confounding factors were also markedly similar. Accidents and suicide was predicted by comorbid anxiety depression.

Depression is a risk factor for all major disease-related causes of death, and is not limited to cardiac mortality or suicide. Case-level anxiety imposes no increased disease-related mortality, but comorbid anxiety depression predicts external causes of death. As the association between depression and cardiac mortality was comparable to the other causes of death combined, and confounding and mediating factors are markedly similar, future investigation as to mechanisms underlying the effect of depression on mortality should not be limited to CVD mortality.