Post by Former NIMH Director Thomas Insel: Mortality and Mental Disorders
It’s easy to overlook the most important health statistic of the past century. Life expectancy has increased dramatically in the U.S., from 51 years in 1910 to nearly 79 years (81 years in women, 76 years in men) in 2010.1 This increase converts to nearly 3 years of additional life every decade or a gain of almost 4 months every year. Unfortunately, reductions in mortality are not shared equally in this country across racial, ethnic, and socio-economic groups. The same Centers for Disease Control and Prevention data show that for African Americans, life expectancy is 75 years (78 years for women and 72 years for men). This evident health disparity has been the subject of intense focus by NIH, prompting, among other efforts, the recent formation of a new institute, the National Institute of Minority Health and Health Disparities (NIMHD).
This brings me to a paper by Walker, McGee, and Druss published online earlier this month in JAMA Psychiatry.2 They ask a simple question: what is the mortality associated with mental illness? Their answer, based on an analysis of 203 studies from 29 countries across 6 continents, should command the attention of anyone who cares about health disparities. The median reduction in life expectancy among those with mental illness was 10.1 years (range from 1.4 to 32 years). Most of this early mortality was attributed to “natural causes” such as acute and chronic co-morbid conditions (heart diseases, pulmonary diseases, infectious diseases); 17.5 percent of deaths appeared related to “unnatural causes” such as suicide and unintentional injuries. Finding more than a doubling of the relative risk of mortality, the authors ask a second question: how many deaths would be averted by eliminating this increased mortality? The answer, based on the prevalence of mental illness globally, is stunning: 8 million people die each year due to mental illness. That is, 8 million deaths could be averted if people with mental illness were to die at the same rate as the general population.
There are some subtle findings in this study that deserve special note. Although the paper reviewed studies from 29 countries, there was no evidence of a difference based on the source population or geographic region being studied. The increase in mortality was reported in studies from the developed and the developing world as well as studies from countries with relatively high levels of mental health care. There was, however, a difference based on when the study was conducted. Studies with more recent baselines showed greater relative risk of mortality, meaning that rather than finding a decrease in health disparities in recent years compared to studies with baselines before 1970, the excessive mortality was actually greater in recent cohorts. It appears that the recent improvements in life expectancy for the general population were not shared by people with mental illness.
This review does not explain the increased mortality, but it does support the longstanding view that people with mental disorders do not die of their condition; they die from the same chronic health conditions as the rest of the population, especially cardiovascular and pulmonary diseases. This is an important insight because it means that mortality may be reduced by addressing the high rates of behaviors such as smoking, substance use, physical inactivity, and poor diet that contribute to chronic and deadly medical conditions. In this new era of parity, equity must be defined not only by equal treatment for mental and physical disorders; parity requires equal treatment of medical disorders in people with mental disorders. Certainly this health disparity is just as important to eliminate as disparities due to race, ethnicity, and socio-economic status.
1 Arias E. United States Life Tables, 2010. Natl Vital Stat Rep. 2014 Nov;63(7):1-63.
2 Walker ER, McGee RE, Druss BG. Mortality in Mental Disorders and Global Disease Burden Implications: A Systematic Review and Meta-analysis. JAMA Psychiatry. 2015 Feb 11. doi: 10.1001/jamapsychiatry.2014.2502. [Epub ahead of print]