a1 Department of Psychological Medicine, Otago University, Wellington, New Zealand
a2 Center for Health Studies, Group Health Cooperative of Puget Sound, Seattle, WA, USA
a3 Health Services Research Unit, Institute Municipal d'Investigacio Medica (IMIM), and CIBER en Epidemiologia y Salud Publica (CIBERESP), Barcelona, Spain
a4 Center for Public Mental Health, Austria
a5 SUNY Stony Brook, Stony Brook, New York, USA
a6 Department of Neurosciences and Psychiatry, University Hospital, Gasthuisberg, Leuven, Belgium
a7 Regional Health Care Agency, Emilia-Romagna Region, Bologna, Italy
a8 Netherlands Institute of Mental Health and Addiction, Utrecht, The Netherlands
a9 Fundació Sant Joan de Déu Research and Development Unit, Barcelona, Spain
a10 Department of Psychiatry, University College Hospital, Ibadan, Nigeria
a11 Shanghai Mental Health Center, Shanghai, People's Republic of China
a12 Department of Health Care Policy, Harvard Medical School, Boston, MA, USA
a13 Fondation MGEN Pour La Santé Publique, Université Paris 5, Paris, France
a14 Mental Health Services, Ministry of Health, Jerusalem, Israel
a15 Department of Epidemiology, National Institute of Psychiatry, Mexico City, Mexico
a16 Institute for Development Research Advocacy and Applied Care (IDRAAC), Beirut, Lebanon
a17 Department of Rural and Indigenous Health, School of Rural Health, Monash University, Victoria, Australia
a18 Colegio Mayor de Cundinamarca University, Bogota, Colombia
a19 National Institute of Mental Health, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
a20 Department of Society, Human Development and Health, Harvard School of Public Health, Harvard University, Boston, MA, USA
Background Physical morbidity is a potent risk factor for depression onset and clearly increases with age, yet prior research has often found depressive disorders to decrease with age. This study tests the possibility that the relationship between age and mental disorders differs as a function of physical co-morbidity.
Method Eighteen general population surveys were carried out among household-residing adults as part of the World Mental Health (WMH) surveys initiative (n=42 697). DSM-IV disorders were assessed using face-to-face interviews with the Composite International Diagnostic Interview (CIDI 3.0). The effect of age was estimated for 12-month depressive and/or anxiety disorders with and without physical or pain co-morbidity, and for physical and/or pain conditions without mental co-morbidity.
Results Depressive and anxiety disorders decreased with age, a result that cannot be explained by organic exclusion criteria. No significant difference was found in the relationship between mental disorders and age as a function of physical/pain co-morbidity. The majority of older persons have chronic physical or pain conditions without co-morbid mental disorders; by contrast, the majority of those with mental disorders have physical/pain co-morbidity, particularly among the older age groups.
Conclusions CIDI-diagnosed depressive and anxiety disorders in the general population decrease with age, despite greatly increasing physical morbidity with age. Physical morbidity among persons with mental disorder is the norm, particularly in older populations. Health professionals, including mental health professionals, need to address barriers to the management of physical co-morbidity among those with mental disorders.
(Received September 14 2007)
(Revised February 22 2008)
(Accepted March 20 2008)
(Online publication March 26 2008)