By Richard B. Karel

A major assessment of public health trends worldwide by the Harvard School of Public Health, the World Health Organization, and the World Bank reveals that neuropsychiatric disorders impose a far heavier burden in both developed and developing nations than previously surmised.

Titled "The Global Burden of Disease," the five-year data compilation completed this June drew on more than 100,000 existing surveys and other data sources, according to editor Christopher J. Murray, M.D., Ph.D., an associate professor of international health economics at the Harvard School of Public Health. The first two of 10 volumes were published in September, with the balance to be published next year.

The project is an ambitious attempt to create a standardized measure for assessing the global burden of mortality and disability from diseases, injuries, and risk factors. It makes that assessment in 1990, projecting to the year 2020. If the methodology is widely accepted, the project has the potential to give policymakers everywhere a uniform measure to guide decisions about allocating scare resources for health-related research and treatment, said Murray.

For psychiatrists who have long asserted that psychiatric disorders deserve a larger share of those scarce resources, the new model provides a jumping off point by establishing that such disorders impose a heavy societal burden. Moreover, according to Murray and others interviewed for this story, psychiatrists must go a step further by making the case that society will get a return on its investment of scarce resources in research and treatment.

"There is an important issue here for people who work on the cost-effectiveness of neuropsychiatric treatments," said Murray. "There is almost no work on the cost-effectiveness of neuropsychiatric treatments in low-income and middle-income countries." The psychiatric community "needs to do the studies to show that you can do something about depression, schizophrenia, and other conditions in an affordable way in low-income countries and middle-income countries. . . .That's very important if you want to convince decision makers that it's not only a big problem but that you can afford to do something about it. I don't think [psychiatrists] have made as convincing a case as they could in terms of rigorous, standard methods in cost-effectiveness."

The standard measure used throughout is the DALY, or "Disability Adjusted Life Year." This is most simply defined as "one lost year of healthy life," and it combines two other measures, the YLL, or "Years of Life Lost," and the YLD, or "Years Lived with Disability."

The global burden of psychiatric conditions has been heavily underestimated, the summary notes. For example, of the 10 leading causes of disability worldwide in 1990, measured in YLD's, five were psychiatric conditions: unipolar disorder, alcohol use, bipolar disorder, schizophrenia, and obsessive-compulsive disorder. It notes that unipolar depression alone accounted for more than one in every 10 YLD's worldwide. In total, neuropsychiatric conditions accounted for 28 percent of all YLD's, 1.4 percent of all deaths, and 1.1 percent of YLL's.

The editors point out that "the predominance of these conditions is by no means restricted to the rich countries," although their burden is highest in the developed world. But they were "the most important contributor to YLD's in all regions except Sub-Saharan Africa," where they accounted for 16 percent of total YLD's.

The figures for selected segments of the population may surprise even those who have long asserted that psychiatric disorders deserve more attention as a cause of disability. Among women aged 15 to 44 worldwide in 1990, for example, major psychiatric disorders made up five of the top six causes of disease burden in DALY's.

The global burden of neuropsychiatric disease is projected to increase from 10.5 percent of the total burden in 1990 to almost 15 percent in 2020. This is a larger proportionate increase than that for cardiovascular diseases, the summary observes.

Measuring health status requires making value judgments, the editors point out. These value judgments include deciding whether years of healthy life in young adulthood are worth more than those in early or late life, standardizing comparisons for disabilities of different severity, and deciding what constitutes an ideal referent of how long people should live.

The summary notes that "there is surprisingly wide agreement between cultures on what constitutes a severe or mild disability." Dementia, for example, is widely regarded as a more severe disability than blindness. Similarly, if people are forced to choose between saving a year of life for a 2-year-old or for a 22-year-old, most prefer to save the 22-year-old.

The most striking trend in neuropsychiatric disorders for the total population, male and female, involves unipolar depression. While it ranked fourth in global burden in 1990, it is projected to rank second (after ischemic heart disease) by the year 2020. The overall burden in years of healthy life lost for a selected group of neuropsychiatric disorders and risk factors is projected to rise from 145.0 million DALY's in 1990 to 203.8 million DALY's in 2020.

Project editor Murray told Psychiatric News that as an internist and economist he had always viewed with skepticism assertions about the heavy impact of psychiatric disease.

"As many nonpsychiatrists are, I was somewhat skeptical of the claims I hear from the psychiatric community about how psychiatric disorders are neglected," said Murray. "If anything, the starting point would have been strong skepticism, so if anything the result was even more surprising." The results were checked five times, he noted.

Many surveys of psychiatric disorders have employed epidemiological indicators _such as "lifetime prevalence"_ unique to psychiatric epidemiology, Murray said. This has made it harder to make the case for the impact of psychiatric disorders to the broader public health community, said Murray.

"I think part of what happened in this study and needs to happen in the future in order to effectively communicate the impact of psychiatric disorders to the larger community is" for psychiatric epidemiologists to employ more standard measures rather than relying so much on "lifetime prevalence," Murray asserted.

"Lifetime prevalence is a very confusing measure because. . .if there are any trends going on, they will be obscured," said Murray. "The other reason it's confusing is recall. The longer the recall period, the more often people's memory is distorted in some way." Whether people underestimate or overestimate, asking them to recall their symptoms over their lifetime "just doesn't work," said Murray.

A striking example of this involves asking women to recall lifetime pregnancies. After about five years, recall starts to decline dramatically.

The epidemiology of tuberculosis (TB) is a good example where a change in methodology helped focus attention on the true scope of a problem, according to Murray. Until the 1980's, epidemiological surveys of TB employed an arcane measure of infection known as the "annual risk of infection," or "ARI," according to Murray. This mystified the public and even other epidemiologists, he said. But in the 1980's, when epidemiologists started talking about how many people were dying from TB and came up with a figure of 3 million, international recognition of the problem soared.

Given the heavy burden of neuropsychiatric disorders and risks measured by the project, what are the implications for future resource allocation?

Since there is only about $50 billion a year available globally for health research, half public, half private, the global burden imposed by a disease or risk factor should be given much weight when research dollars are allocated, Murray said.

"I do not know what fraction of the $50 billion each year is spent on neuropsychiatric conditions," he added. "I strongly suspect, however that the fraction of burden that neuropsychiatric conditions account for" exceeds the research dollars applied.

Using the DALY's to help allocate scarce resources is "the sort of thing I hope is done with these numbers," said Murray. "And maybe that will lead to an informed policy debate about how U.S. monies for research are allocated."

When it comes to using current dollars for treating disease conditions, "then you need other information in addition to burden of disease," Murray commented. You need to know what you can do about disease now. "The term here is 'cost-effectiveness.' So you need to be concerned about how many DALY's do you save through an intervention and how much does it cost. With that information and burden of disease information, you can start translating the information into some kind of priority for intervention."

If, for example, a condition has no or uncertain treatment, it would make sense to spend more money on research, but little sense to spend more on current treatment, according to Murray. In other words, the ranking of current burden does not necessarily translate into a priority for therapeutic intervention. That depends on the efficacy and cost of available treatment, he explained.

The project's findings on psychiatric disease highlight a tragic disparity, said consultant Arthur Kleinman, M.D., chair of the Harvard School of Social Medicine.

"The great tragedy in our field is that the resources are not commensurate with the size of the problem," said Kleinman. "This report gives real support on the economic side that these problems are significant."

The report, however, places a burden on "groups like APA. . .to make clear that these are the biggest problems," Kleinman added. "The implications of our new understanding of morbidity is that more funds need to go into this area. This is true not just for industrialized societies but also in places like Tanzania, Brazil, and India."

Darrel Regier, M.D., M.P.H. is director of the Division of Epidemiology and Services Research at the National Institute of Mental Health (NIMH).

The great value of the project is providing "the same yardstick" to measure the impact of all kinds of diseases and disorders, he noted. This places psychiatric disorders "squarely in the category of legitimate diseases rather than in the category of moral failure or a question of will," Regier observed. "When science can be brought to bear on these illnesses, it has an objectivizing, destigmatizing effect. People feel that improvement can actually be obtained by investment in research."

How research monies should be allocated is a complex issue, Regier said. "It must be guided on the basis of several criteria. What is the public health burden?" is one key criterion. Another is "the issue of basic research leading to long-term benefits." NIMH would like to refine the measures used in the Global Burden of Disease Project, so they become "even more objective," Regier said.

Staff writer Mark Moran contributed to this article.

(Psychiatric News, November 1, 1996)