a1 Department of Psychiatry, The Chinese University of Hong Kong, Hong Kong, PRC, USA
a2 Hong Kong Mood Disorders Center, The Chinese University of Hong Kong, Hong Kong, PRC, USA
a3 Department of Psychology, University of Pennsylvania, Philadelphia, USA
a4 Sant Joan de Deu-SSM, Barcelona, Spain
a5 University of Cape Town, UCT Department of Psychiatry, Cape Town, South Africa
a6 Health Services Research Unit, IMIM-Hospital del mar, CIBER en Epidemiologia y Salud Publica (CIBERESP), Barcelona, Spain
a7 Center for Public Mental Health, Gösing a.W, Austria
a8 SUNY Stony Brook, Stony Brook, New York, NY, USA
a9 University Hospital Gasthuisburg, Leuven, Belgium
a10 Regional Health Care Agency, Emilia-Romanga Region, Italy
a11 Netherlands Institute of Mental Health and Addiction, Utrecht, The Netherlands
a12 Department of Psychiatry, University College Hospital, Ibadan, Nigeria
a13 Hiroshima International University, Higashi-Hiroshima, Japan
a14 Institute for Development, Research, Advocacy, and Applied Care (IDRAAC), St. George Hospital University Medical Center, Beirut, Lebanon
a15 Hospital Fernand Widal, Paris, France
a16 Ministry of Health, Mental Health Services, Jerusalem, Israel
a17 National Institute of Psychiatry, Mexico City, Mexico
a18 Department of Rural and Indigenous Health, School of Rural Health, Faculty of Medicine, Nursing and Health Sciences, Monash University, Victoria, Australia
a19 Colegio Mayor de Cundinamarca University, Bogotá, Colombia
a20 Department of Health Care Policy, Harvard Medical School, Boston, USA
Background A number of western studies have suggested that the 6-month duration requirement of generalized anxiety disorder (GAD) does not represent a critical threshold in terms of onset, course, or risk factors of the disorder. No study has examined the consequences of modifying the duration requirement across a wide range of correlates in both developed and developing countries.
Method Population surveys were carried out in seven developing and 10 developed countries using the WHO Composite International Diagnostic Interview (total sample=85 052). Prevalence and correlates of GAD were compared across mutually exclusive GAD subgroups defined by different minimum duration criteria.
Results Lifetime prevalence estimates for GAD lasting 1 month, 3 months, 6 months and 12 months were 7.5%, 5.2%, 4.1% and 3.0% for developed countries and 2.7%, 1.8%, 1.5% and 1.2% for developing countries, respectively. There was little difference between GAD of 6 months' duration and GAD of shorter durations (1–2 months, 3–5 months) in age of onset, symptom severity or persistence, co-morbidity or impairment. GAD lasting 12 months was the most severe, persistently symptomatic and impaired subgroup.
Conclusions In both developed and developing countries, the clinical profile of GAD is similar regardless of duration. The DSM-IV 6-month duration criterion excludes a large number of individuals who present with shorter generalized anxiety episodes which may be recurrent, impairing and contributory to treatment-seeking. Future iterations of the DSM and ICD should consider modifying the 6-month duration criterion so as to better capture the diversity of clinically salient anxiety presentations.
(Received July 16 2008)
(Revised September 26 2008)
(Accepted October 07 2008)
(Online publication December 18 2008)