Department of Primary Care and Population Sciences, University College London, UK
Department of Primary Care and Population Health, University College London Medical School and Medical Research Council General Practice Research Framework, UK
Department of Psychiatry, University of Granada, Spain
vab, MD, PhD
Department of Family Medicine, University of Ljubljana, Slovenia
Faculty of Medicine, University of Tartu, Estonia
University Medical Center, Utrecht, The Netherlands
Faculdade Ciências Médicas, University of Lisbon, Portugal
Departamento de Psiquiatraía y Salud Mental, Universidad de Concepción
Department of Mental Health Sciences, University College London, UK.
Correspondence: Correspondence: Christian Bottomley, Infectious Disease Epidemiology Unit, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK. Email: christian.bottomley{at}lshtm.ac.uk
Background
Factors associated with depression are usually identified from cross-sectional studies.
Aims
We explore the relative roles of onset and recovery in determining these associations.
Method
Hazard ratios for onset and recovery were estimated for 39 risk factors from a cohort study of 10 045 general practice attendees whose depression status was assessed at baseline, 6 and 12 months.
Results
Risk factors have a stronger relative effect on the rate of onset than recovery. The strongest risk factors for both onset and maintenance of depression tend to be time-dependent. With the exception of female gender the strength of a risk factors effect on onset is highly predictive of its impact on recovery.
Conclusions
Preventive measures will achieve a greater reduction in the prevalence of depression than measures designed to eliminate risk factors post onset. The strength of time-dependent risk factors suggests that it is more productive to focus on proximal rather than distal factors.
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