Elie G Karam1, Nancy Sampson2, Lynn Itani3, Laura Helena Andrade4, Guilherme Borges5, Wai Tat Chiu2, Silvia Florescu6, Itsuko Horiguchi7, Zahari Zarkov8, Hagop Akiskal9. 1. Institute for Development, Research, Advocacy and Applied Care (IDRAAC), Beirut, Lebanon; Department of Psychiatry and Clinical Psychology, Saint George Hospital University Medical Center, Balamand University, Faculty of Medicine, Beirut, Lebanon. Electronic address: egkaram@idraac.org. 2. Department of Health Care Policy, Harvard Medical School, Boston, MA, USA. 3. Institute for Development, Research, Advocacy and Applied Care (IDRAAC), Beirut, Lebanon. 4. Institute of Psychiatry, University of Sao Paulo Medical School, São Paulo, Brazil. 5. Division of Epidemiological and Psychosocial Research, National Institute of Psychiatry (Mexico) and Metropolitan Autonomous University, Mexico City, Mexico. 6. National School of Public Health, Management and Professional Development, Bucharest, Romania. 7. Faculty of Medicine, Juntendo University, Tokyo, Japan. 8. National Center of Public Health and Analyses, Department Mental Health, Sofia, Bulgaria. 9. International Mood Center, University of California at San Diego, La Jolla, CA, USA.
Abstract
BACKGROUND: To investigate if the prevalence of bipolar disorder in epidemiologic studies is an underestimate, as suggested by clinical studies. METHODS: We analyzed data from 8 countries that participated in the World Mental Health Survey Initiative (n=47,552). We identified 6.8% and 18.9% of the sample who we think were screened out inappropriately (SCI) from the euphoric and irritable bipolar sections respectively. We compared them to those who were allowed to continue the section (CONT, 2.6% of the sample for euphoric; 1.0% for irritable) and to the reference group (REF, 69.5% of the sample). RESULTS: The SCI group had consistently higher rates of major depression (29.1% vs. 6.4%), earlier age of onset (24.3y vs. 32.4y), more suicide attempts (13.3% vs. 5.9%), and more episodes (4.2 vs. 2.7) than the REF for the euphoric group. Similar findings exist for the irritable group. Also, comorbidity with anxiety, disruptive behavior disorders and substance use were much higher than the REF. LIMITATIONS: As with all epidemiologic studies, recall bias cannot be ruled out. CONCLUSIONS: The findings above suggest that a number of the SCI subjects belong to the bipolar group. A revision of instruments used in epidemiologic research will probably prove what clinical studies have been showing that bipolar disorder is more common than has been reported.
BACKGROUND: To investigate if the prevalence of bipolar disorder in epidemiologic studies is an underestimate, as suggested by clinical studies. METHODS: We analyzed data from 8 countries that participated in the World Mental Health Survey Initiative (n=47,552). We identified 6.8% and 18.9% of the sample who we think were screened out inappropriately (SCI) from the euphoric and irritable bipolar sections respectively. We compared them to those who were allowed to continue the section (CONT, 2.6% of the sample for euphoric; 1.0% for irritable) and to the reference group (REF, 69.5% of the sample). RESULTS: The SCI group had consistently higher rates of major depression (29.1% vs. 6.4%), earlier age of onset (24.3y vs. 32.4y), more suicide attempts (13.3% vs. 5.9%), and more episodes (4.2 vs. 2.7) than the REF for the euphoric group. Similar findings exist for the irritable group. Also, comorbidity with anxiety, disruptive behavior disorders and substance use were much higher than the REF. LIMITATIONS: As with all epidemiologic studies, recall bias cannot be ruled out. CONCLUSIONS: The findings above suggest that a number of the SCI subjects belong to the bipolar group. A revision of instruments used in epidemiologic research will probably prove what clinical studies have been showing that bipolar disorder is more common than has been reported.