Research Centre for Health Promotion, Faculty of Psychology, University of Bergen, Norway, and Institute of Psychiatry, King's College London, UK and Norwegian Institute of Public Health, Division of Mental Health, Oslo, Norway
Department of Research and Development, Levanger Hospital, Norway, and Department of Neuroscience, Unit for Psychiatry and Behavioral Science, Faculty of Medicine, National University of Science and Technology, Trondheim, Norway
Research Centre for Health Promotion, Faculty of Psychology, University of Bergen, Norway
Institute of Psychiatry, King's College London, UK
Correspondence: Arnstein Mykletun, Mental Health Epidemiology, Research Centre of Health Promotion, Faculty of Psychology, University of Bergen, Christiesgt 13 N-5015 Bergen, Norway. Email: Arnstein.Mykletun{at}uib.no
None.
R.S. is funded by NIHR Biomedical Research Centre for Mental Health, the South London and Maudsley NHS Trust, and the Institute of Psychiatry, King's College London.
Background
Depression is reported to be associated with increased mortality, although underlying mechanisms are uncertain. Associations between anxiety and mortality are also uncertain.
Aims
To investigate associations between individual and combined anxiety/depression symptom loads (using the Hospital Anxiety and Depression Scale (HADS)) and mortality over a 3–6 year period.
Method
We utilised a unique link between a large population survey (HUNT–2, n = 61 349) and a comprehensive mortality database.
Results
Case-level depression was associated with increased mortality (hazard ratio (HR) = 1.52, 95% CI 1.35–1.72) comparable with that of smoking (HR = 1.59, 95% CI 1.44–1.75), and which was only partly explained by somatic symptoms/conditions. Anxiety comorbid with depression lowered mortality compared with depression alone (anxiety depression interaction P = 0.017). The association between anxiety symptom load and mortality was U-shaped.
Conclusions
Depression as a risk factor for mortality was comparable in strength to smoking. Comorbid anxiety reduced mortality compared with depression alone. The relationship between anxiety symptoms and mortality was more complex with a U-shape and highest mortality in those with the lowest anxiety symptom loads.
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