The Global Burden of Disease Study was a five-year study conducted by the Harvard School of Public Health on behalf of the World Health Organization and the World Bank. The study began in 1992, and its goal was to quantify and compare the burden of premature mortality, disease, and injury across the various cultures and countries of the world community.

Until recently, the most common measure of a society's health status was the rate of death per population, or the rate of death by age per population. The exclusive dependence on death rates to evaluate health status has long been criticized. However, finding a way to compare diseases, disabilities, and injuries across international populations has been extraordinarily difficult. As part of the Global Burden of Disease Study, researchers created a measure of health status that accounted for disability along with the number of deaths and the impact of premature death.

The first volume of the final product of the study is a 990-page publication entitled The Global Burden of Disease: A Comprehensive Assessment of Mortality and Disability From Diseases, Injuries, and Risk Factors in 1990 and Projected to 2020 (1). Volume 1 provides worldwide epidemiological information on 240 conditions. The statistical techniques used to derive the formula for establishing premature death and the disability measures developed for the study represent a new approach to evaluating a society's health. A new index called the disability adjusted life year—the DALY—has now become the international standard for evaluating and comparing a society's burden of disease (2).

The calculation of the DALY is complex and depends on the sum of numbers representing the years of life lost (YLL) and years lived with disability (YLD). Each of these values is in turn derived from complicated mathematical formulas, but even the mathematically challenged can easily understand the concept of YLD, which is defined as time lived in health states that are less than perfect. This concept is especially easy for psychiatrists to understand: they rarely save lives, but they generally focus on states of health that can be euphemistically described as less than perfect.

The concept of the DALY is useful because the traditional use of death rates to evaluate a society's health status may not reflect the economic and social burdens that illnesses impose on a society. From the viewpoint of individuals who are thrust into the caretaking role, illnesses with a prolonged course can impose a greater emotional and economic burden than illnesses that end in a relatively quick death

The findings of the Global Burden of Disease Study demonstrate clearly that disability plays a central role in determining the overall health status of a population. Yet that role has been almost invisible to public health authorities. The study shows that the leading causes of disability are substantially different from the leading causes of death, thus casting serious doubt on the practice of judging a population's health from its mortality statistics alone.

The findings may be surprising to some but not necessarily to psychiatrists. The study shows that the burden of psychiatric conditions, such as depression, alcohol dependence, and schizophrenia, has been heavily underestimated. Although psychiatric conditions are responsible for little more than 1 percent of deaths, they account for almost 11 percent of disease burden worldwide. Of the ten leading causes of disability worldwide in 1990, measured in YLD, five were psychiatric conditions: unipolar depression, alcohol abuse and dependence, bipolar affective disorder, schizophrenia, and obsessive-compulsive disorder (see box).

The study made projections about disease burden in the year 2020 on the basis of DALYs but not YLDs, perhaps because years lived with disability are more difficult to predict (see box with list of predictions). This is particularly true for psychiatric conditions, because many drug treatments are only partially effective. It is entirely possible that in 2020 unipolar depression will fall to third place as a cause of disability, as predicted by the study, because improved treatments will lead to recovery.

The rank order of schizophrenia in 2020 is more difficult to predict, because the treatment results are less clear. Current treatment of schizophrenia is somewhat less than curative but somewhat more than palliative. Drug therapy for schizophrenia has complex effects on the global burden of disease. Currently, the savings attributable to drug therapy result from the reduction in direct hospitalization costs. However, people who have schizophrenia are now living longer because of decreased suicide rates and better psychiatric care, and many will continue to live in economic dependency. As a result they will incur the increased costs of medical illnesses associated with advancing age, such as heart disease, diabetes, chronic obstructive pulmonary disease, osteoporosis, and arthritis. Perhaps an ecosystem-like balancing principle is at play, wherein the attenuation of one illness is followed by a proliferation of other illnesses to occupy the empty space.

Given the relatively high cost of atypical antipsychotic medications, it appears to be safe to say that even if some people who have chronic schizophrenia improve sufficiently to be less than totally disabled, many will continue to be dependent on public subsidies because they cannot afford the medication that produced the improvement (3). Given the increased cost and effectiveness of these medications, the resulting decrease in suicide rates, and the greater longevity and higher medical costs of people who have schizophrenia, schizophrenia may move closer to the top of the list in 2020 as measured by DALYs, even though the study's projections do not place it in the list of the top ten.

Nothing better illustrates the hazards of predicting the future socioeconomic impact of psychiatric treatments than the story of chlorpromazine. Chlorpromazine, which was first used in the United States in 1953, and the antipsychotics and other psychiatric medications that were later developed have changed the world in ways that no one could have predicted. The prediction of global burdens in the 21st century is even more difficult.

As noted, one of the socioeconomic effects of antipsychotic medications is the increased medical costs attributable to patients' greater longevity. Many other socioeconomic changes were brought about directly or indirectly by antipsychotic drugs:

• the migration of most chronically mentally ill patients out of state hospitals

• the transformation of many state hospitals to exclusive repositories for the criminally insane

• the return of many chronically mentally ill patients to their families

• the ability of some chronically mentally ill patients to resume their careers or education

• the transfer of many other chronically mentally ill patients to special residential facilities in the community

• the creation of domiciliary facilities as alternatives to hospitalization in which on-site treatment is provided

• the transfer of some mentally ill patients to jails and prisons

• the transfer of some elderly patients with mental illness to nursing homes

• the transformation of some nursing homes into geriatric mini-mental hospitals

• the proliferation of acute psychiatric treatment facilities in community hospitals

• the creation of special nonhospital treatment facilities in community mental health centers, rehabilitation programs, substance abuse clinics, psychosocial rehabilitation clubhouses, shelters for the homeless, and elsewhere

• the creation of a minivan transportation system to transport people with mental illness to physicians' offices, clinics, activity centers, partial hospitalization programs, and other programs

• the passage of rights-driven legislation based on the least-restrictive alternative

• the passage of other laws, such as the Community Mental Health Centers Act, designed to facilitate the treatment of persons with mental illness in the community

• the creation of special industries, large and small, dedicated to the treatment and rehabilitation of the mentally ill

• the emergence of a homeless mentally ill constituency that is either unwilling or unable to live in specialized community facilities

• the growth of special neighborhoods characterized by urban decay and poverty in which people with mental illness reside

• the rise of the NIMBY—not in my back yard—movement among homeowners wishing to prevent people with mental illness from living in their neighborhoods

• the rise of consumer advocacy groups, such as the National Association for Rights Protection and Advocacy, the purpose of which is to fight the use of medications and question the biological basis of mental illness

• the rise of groups, such as the National Alliance for the Mentally Ill, created by families of people with mental illness in order to defend the rights of the mentally ill and lobby for increased funding for treatment and research

• the decline in psychoanalytically dominated faculties in medical schools

• the demise of purely psychogenic etiologic theories of schizophrenia involving "schizophrenogenic mothers," "double-binds," and "family skews and schisms," and other assorted forms of parent-bashing

• the rise of legislative militancy as a legitimate means of expanding prescription-writing privileges to nonmedical professionals

• the increased pressure by managed care companies to reduce psychotherapy services

• the increased incentive to discover medications for psychiatric conditions formerly thought to be treatable only by psychotherapy

• the creation of a vast potential market for antipsychotic drugs for formerly hospitalized patients and the realization by pharmaceutical drug houses that the funding for this market could be extracted from public budgets.

These changes transcend the concept of disease burden and are best understood within the context of psychopharmacosocioeconomics—a personally constructed but useful neologism for the study of the ways in which psychiatric drugs have had a worldwide impact on social and economic systems (3). However, it is useful to consider these changes when attempting to predict the global burden of disease, because many of them effect the YLD measure—years lived with disability. Some will shorten years lived with disability—for example, by making it possible for some people with mental illness to resume careers or education. Others will prolong years lived with disability, such as when people with mental illness are housed in jails and prisons. The variety and extent of the changes listed above should make it clear that predictions about the disease burden of schizophrenia in the year 2020—or in any other year—are fraught with uncertainties.

Psychiatric drugs have had a profound influence on society. Their influence is unappreciated because we have become used to the sight of people with chronic psychosis, unwashed and deranged, wandering the streets in states of obvious neglect. There was a time when such deplorable tableaus did not exist, although this may not be conceivable to younger people. We have become inured to the effects of psychopharmacosocioeconomic negligence, because we are confronted daily with its results and we do not connect the dots. The dots are the invention of antipsychotic drugs leading to the closure of state hospitals leading to community placements (with various states of supervision or neglect) leading to the worldwide endorsement of the least-restrictive alternative as a morally justifiable principle for the treatment of the mentally ill and, in many instances, leading to a sink-or-swim mental health policy.

As a result, we practice the adaptive mechanism of numbing down—a reaction that one psychiatrist has described as "a universal and necessary complement to awareness" (4)—an adaptation that permits us to disregard unpleasantness and attend to the compelling realities of our existence without the distractions created by the problems of others pushing shopping carts while exercising the freedoms afforded to them by virtue of the "least-restrictive alternative."

Dr. Fleishman is staff psychiatrist at St. Francis Memorial Hospital, 909 Hyde Street, Suite 115, San Francisco, California 94109 (e-mail, martin120@aol.com). Steven S. Sharfstein, M.D., is editor of this column.