Lifting the shroud on depression and premature mortality: a 49-year follow-up study

Numerous studies have shown higher rates of death from natural causes in the years immediately following an episode of clinical depression. The longer term relationship of depression to excess mortality is less clear because relatively few studies have followed the same cohort of patients for more than 10 years. The present paper reports on the findings following the same cohort of patients 49 years after discharge.

Patients who were diagnosed with depression in the Chichester/Salisbury Catchment Area Study were followed for 49 years. The incidence of death from natural causes in the clinical population was compared with population rates adjusted for age and sex.

The results suggest that clinical depression may have enduring effects on physical health that emerge later in life, the significance of which have so far remained undetected. Further analyses of death rates by age and sex suggest that: a.) Depression has a stronger impact on mortality among women. b.) Excess mortality starts to emerge at an earlier age among women.

Because prior studies of depression and mortality have typically followed patients for fewer than 25 years, the long-term impact of major depression has remained undetected. The results are consistent with the view that depression has a negative impact on health that spans multiple decades.

The association between mortality and depression could arise if prolonged treatment with antidepressant medication increases mortality. The association found between depression and mortality might also reflect differences in the quality of medical care that is provided to clinically depressed individuals. The present study does not control for factors that are confounded with depression (e.g., diet, exercise), nor does it utilize a matched control group.

The pathways linking depression and mortality are likely to be complex and multifactorial in nature. The major implication of the present work is to suggest that such pathways link depression with long-term, as well as short-term differences in mortality.