According to 12-month prevalence statistics, an estimated 2.6% of US adults have bipolar disorder.1 While the disease is relatively uncommon, it is associated with significant disability due to the severity of symptoms and the early age of onset. Though approximately 83% of US cases are considered severe, only 18.8% of adult patients in the US receive minimally adequate treatment despite the availability of effective treatments, and treatment rates are particular low in low- and middle-income nations.1 Additionally, the disorder is often underdiagnosed or misdiagnosed.
The burden related to bipolar disorder is growing along with the population and the number of people living to older ages. It is important to establish accurate prevalence rates to inform mental health policy, research and funding priorities, and intervention strategies to help reduce the burden associated with the disease. To that end, researchers from the University of Washington in Seattle and several Australian universities investigated the global prevalence and burden of bipolar disorder based on data from the Global Burden of Disease Study 2013 (GBD 2013). Their findings were reported in Bipolar Disorders in August 2016.2
The authors conducted a systematic literature review and used Bayesian meta-regression modeling to determine the global prevalence of bipolar disorder. Cases were included in the analysis if they met DSM-IV or ICD-10 criteria for bipolar I disorder, bipolar II disorder, cyclothymia, or bipolar disorder not otherwise specified. They then calculated the associated years lived with disability (YLDs) and disability-adjusted life years (DALYs) to assess the global burden of the disorder. These are calculated so that “one DALY is equivalent to the loss of a healthy year of life due to a particular disease or injury,” the authors explained in the paper. The estimates of burden were adjusted for comorbidity with other diseases.
Video news update: Dr. Nicole Foubister of NYU’s Child Study Center speaks about bipolar disorder. Watch now.
The results indicate that the prevalence of the bipolar disorder rose by 49.1% between 1990 and 2013, from 32.7 million to 48.8 million. However, the increase was entirely explained by population growth and aging. In 2013, there were 9.9 million DALYS due to bipolar disorder–5.5 million among females and 4.4 million among males–making it the fifth leading cause of DALYs among the mental and substance use disorders (SUDs) examined. “DALYs were evident from age 10 years, peaked in the 20s, and decreased thereafter,” and they were relatively consistent across countries, according to the paper.
In light of the increasing global burden linked with bipolar disorder, it is imperative that “resources be directed towards not only improving the coverage of evidence- based intervention strategies for bipolar disorder but also establishing preventive strategies to prevent new cases of the disorder from occurring,” the authors wrote.
1. National Institutes of Health: National Institute of Mental Health. Bipolar disorder among adults. Retrieved 9/8/16 from http://www.nimh.nih.gov/health/statistics/prevalence/bipolar-disorder-among-adults.shtml
2. Ferrari AJ, Stockings E, Khoo JP, et al. The prevalence and burden of bipolar disorder: findings from the Global Burden of Disease Study 2013. Bipolar Disord. 2016; 18(5):440-50.