Depression: The Public Health Dimensions

Depression: The Public Health Dimensions

The words above belong to author William Styron, and they describe his first episode of major depression.

The experience belongs to millions.

For Styron, it began with gnawing perception that all was not right in his world. Gradually it evolved into full-blown pain, at once unfocused and unbearable, he says.

For others, depression descends like a fog. They withdraw, become fatigued, sleep too little (or too much), shun food (or overeat), lose interest in friends, family, life itself. Their voices flatten. In late stages of the disease they take on what psychiatrist Peter Kramer, author of Against Depression, calls a “typical look. Blank stare, downcast eyes, knitted brow. Head supported by a hand, or face masked by one. This expression is one that artists have depicted for centuries, what doctors call the facies of the illness.”

Between 18 and 20 million Americans—17 percent of the population—suffer from depression, women more than men. Worldwide, depressive illnesses account for 75 to 85 percent of all suicides. Uni-polar, or clinical, depression is one of the top five leading causes of disability on our planet. Together with bipolar disorder, or manic depression, it is costlier and more burdensome than any other ailment except cardiovascular disease.

“Depression destroys families. It ruins careers. It ages patients prematurely,” Kramer writes. “Depression is debilitating, progressive and relentless in its downhill course, as tough and worthy an opponent as any a doctor might choose to combat.”

Increasingly, though, it’s not just doctors who are battling this scourge. Once an ordeal suffered in private and often in shame, depression is now a major public health issue. Some would argue it’s the major public health issue of this century.

“More than any other health condition,” says School of Public Health Assistant Professor Daniel Eisenberg, whose research focuses on mental health interventions for the young, “depression represents a person’s overall well-being. In that sense, treating depression gets directly at public health’s most important outcome.”

Not long ago, society viewed depression as a moral weakness, not a physical disease, and people kept it a secret. Insurers paid little or nothing for treatment. Combined, these two factors—stigma and cost—kept people out of care, says Kyle Grazier, professor of health management and policy, who is currently examining the integration of depression and primary care through studies funded by the Robert Wood Johnson Foundation and Blue Cross Blue Shield of Michigan.

Grazier notes the irony that a disease like depression has for decades been relegated to public health’s back burner. “Over half the costs in mental health today are due to depression,” she points out. What’s more, depressed people are more likely to do damage to themselves or others and more likely to suffer from chronic diseases, and the fact that they have depression intensifies chronic ailments.

“Depression can contribute to obesity,” Grazier continues. “It’s hard to stop smoking when you’re depressed. Depression keeps people out of the workplace in huge numbers, reduces productivity at school and work, and has tremendous ramifications for our economy.” People who suffer from depression are nearly 28 times more likely to miss work because of emotional disability.

Depression touches on issues fundamental to public health, such as mental health parity: who gets access to mental health care, when and how? Depression underscores racial and ethnic differences in health. African-American women, for example, have a significantly lower depres-sion rate than white women, and overall, fewer blacks than whites commit suicide. At the same time, African Americans are less likely than whites to seek outpatient care for depression.

Socioeconomically disadvantaged populations are often at greater risk for depression. Sandro Galea, an associate professor of epidemiology who studies the ways that social context shapes mental health, has found that residents of so-called “bad” neighborhoods—neighborhoods with poor physical infrastructure, indoors and out, and high levels of income inequality—are more likely to suffer depression, “independent of individual characteristics,” Galea emphasizes. “So what that means is if you take me, and you put exactly me—the same person—in one environment versus another environment, I am more likely to be depressed if the environment is poor than if the environment is good.”

In another set of studies, Galea has found that depression rates spike in the wake of both natural and manmade disasters, such as the September 11, 2001, attacks in New York and Washington and the 2003 bombings in Madrid. Typically, the prevalence of depression after a major disaster is about twice the baseline “of what you’d expect,” says Galea, who co-directs the Disaster Research Education and Mentoring Center, a collaboration between the University of Michigan and the Medical University of South Carolina.

In the aftermath of Hurricane Katrina, Galea expects to see heightened rates of depression along the Gulf Coast, particularly because so many people were displaced and therefore lost the “immensely protective” force of social networks and supports. Galea hopes to conduct studies in the region early next year.

Together, all of these facts argue for depression as a major public health issue, and indeed, says Grazier, in the past decade the disease has finally emerged as such.

In the past five years, she reports, health officials have begun to view depression as a chronic disease, and it now turns up in the nation’s large disease-management programs.

The World Health Organization lists depression as one of the most disabling disorders in the world.

In its September 9, 2005, Morbidity and Mortality Weekly Report, the Centers for Disease Control and Prevention ack-nowledged that depression is a risk factor “for such chronic illnesses as hypertension, cardiovascular disease, and diabetes, and can adversely affect the course and management of these conditions.” The CDC called for public health agencies to “incorporate mental health promotion into chronic disease prevention efforts.”

Two years ago, the National Insti-tutes of Mental Health launched a public service campaign called “Real Men. Real Depression.” Designed to raise awareness that “depression is a major public health problem affecting an estimated six million men annually,” the campaign features real-life stories of American men who live with depression, among them a firefighter, a national diving champion, and a retired Air Force sergeant. Under the auspices of its Depression Center, the UM leads national efforts to roll out this campaign to college campuses across the country.

Created in 2001, the UM Depression Center is itself the nation’s first comprehensive center devoted to depressive illness research, treatment, education, and public policy. Its executive director, John Greden, who also chairs the UM Medical School Department of Psychiatry, says “prevention—real prevention—is a foundation of our vision. We have much to do to achieve that dream, but no other long-term goal is acceptable.” Greden is hopeful the UM center will be the first in a national network of such centers.

After centuries of misconception, depression is at last losing its stigma. “Everybody has a relative or a friend or a spouse or a coworker who has this,” says Greden. “They understand it is an illness—they get it.”

And because they get it, they see depression with fresh eyes. But Greden, Grazier, Galea, and others wonder whether that will be enough. What will it really take, they ask, to diagnose, treat, and ultimately prevent this modern plague?

Like diabetes and cardiovascular disease, depression is a “biological illness that is linked to events of living,” Greden says. Although their underlying causes vary, all depressive illnesses are brain disorders, and all have a biological foundation. “It has taken people a long time to recognize that, which is part of the stigma,” he says.

The two most basic types of depression, clinical and bipolar, differ in key ways, but both can be life-threatening.

Clinical depression has as its primary feature depressive symptoms: sadness, lethargy, a loss of interest in things, sometimes coupled with pain, fatigue, changes in appetite, sleep loss, or in some cases its opposite, hypersomnia.

Bipolar disorder includes the propensity for episodes of clinical depression, but in addition it features episodes of hypomania. Greden describes those who suffer from bipolar disorder as “the movers, doers, shakers of the world. They are boundless in their energy. They talk faster, and they have a sensuality, an excitement.” Gradually, he says, they slide into “a full-fledged manic state, and some become delusional.”

While the precise etiology of depression “remains elusive,” notes Galea, scientists are actively trying to understand its genetic origins. SPH and Depression Center biostatistician Sebastian Zöllner, who is working with UM researchers to identify the genetic variants that underlie depression, is hopeful that someday we’ll know enough about DNA’s influence on depression to be able to better diagnose and treat the disease (see Future Findings The Search for Depression's Genetic Origins).

What is clear is that first-degree relatives of people with major depression are themselves at two to three times greater risk for depression, although as Galea points out, socioenvironmental factors and environmental stressors also play a significant role in the development of the disorder. Victims of nonsexual assault, for example, are 50% more likely to suffer from depressive symptoms than those who have not been assaulted.

Although depression usually starts in young adulthood—most often between the ages of 15 and 24—it can also strike children and adults of all ages. If untreated, it grows progressively more severe, with later episodes lasting longer than early ones. The timing of episodes varies. One can go years without depressive symptoms, then suddenly the fog descends again. Often it’s because of some new stress.

Scientists are just now beginning to understand the process by which this happens. Neurotrophins, the growth-promoting chemicals that nourish our neurons, atrophy when exposed to stress, and in turn deprive brain tissue of vital nutrients. Magnetic resonance images show that people with chronic depression have a smaller hippocampus—which helps regulate stress, emotions, and our response to fear—than matched controls.

Computer-aided mapping reveals, as well, that in individuals who suffer from depression, cells in the prefrontal cortex —that part of the brain concerned with cognition, planning, and other capacities related to social functioning, as well as with eagerness, or the anticipation of pleasure—are weak, disorganized, and disconnected.

“Most of the recent findings suggest that if you can successfully treat depression, you can do some restoration of these neuronal degenerative changes,” Greden says.

Currently, the most effective treatments for depressive illnesses are combinations of antidepressants, targeted psychotherapies, and ancillary interventions such as exercise, sleep, and nutrition. Also helpful is interpersonal therapy that focuses on relationship issues that promote stress. But Greden is optimistic that within 10 to 15 years, research advances will yield even better interventions.

Meanwhile, simply getting people to seek treatment for depression is a colossal challenge. In the June 2005 issue of the Archives of General Psychiatry, authors Thomas R. Insel and Wayne S. Fenton reported that in a recent national survey, 60 percent of respondents with any type

of mental disorder deemed “moderate to serious”—including depression— received no treatment whatsoever.

Clearly, wrote Insel and Fenton, “psychiatry faces one of the greatest public health challenges in contemporary medicine.”

How do you know if you’re depressed?

That question, says Grazier, who serves on the steering committee of the UM Depression Center, is pivotal. Before psychiatrists and other specialists can begin thinking about treating the disorder, it’s paramount that primary care practitioners be trained to recognize the symptoms of depression.

“Our hypothesis is that the only way to treat depression is by integrating care—having primary-care physicians work with mental health specialists,” Grazier explains. “There is a newfound recognition that unless and until you attack the system with new tools, it’s very difficult for family practitioners to ask the right questions. The vast majority of people with depression—some estimates say over 75 percent—never seek out a mental health specialist but instead seek care through their primary care practitioner.”

In addition to learning how to recognize depression, she says, primary-care physicians must have up-to-date information on drug therapies and other interventions. Nurse- or care-managers may need to be added to the mix, too, in order to monitor patients diagnosed with depression.

Many experts are asking whether children should be screened for depression in school, much as they’re now screened for vision and hearing loss. The final report of the President’s New Freedom Commission on Mental Health, issued in May 2003, called for the implementation of “a national effort to focus on mental health needs of young children and their families that includes screening.”

Eisenberg believes school-based mental health resources are one of the most promising avenues toward improving the overall mental health of children. He’s concerned about mental health interventions for young people in general, and is currently conducting a web-based survey of 4,500 UM undergraduates to determine how well students’ mental health needs are being met, particularly among those with depression.

Eisenberg cites a recent survey that found that one of every ten college students in the United States had seriously considered suicide in the past year (suicide attempts are significantly lower, he notes). So “there’s much to be gained by interventions at this stage,” he says.

He hopes to quantify the prevalence of anxiety and depressive symptoms on the UM campus and to determine “why people who should get these services don’t.” Ultimately he’ll share his findings with UM administrators, researchers, and health professionals, who can then design and implement appropriate interventions.

Before becoming SPH dean, Ken Warner, the Avedis Donabedian Distinguished University Professor of Public Health, chaired the Michigan Healthy Community Initiative Task Force, a campus-wide effort to improve health care in the UM community. “One of the primary areas we looked at was depression,” he says. “It’s often a hidden disease, yet it afflicts large numbers of our own UM community—faculty, staff, and students. Depression imposes an enormous burden on these individuals, and a high cost on our community as a whole. At SPH, we have a crucial role to play in addressing this complex issue, especially in collaboration with the UM Depression Center.”

It’s not just young people who fail to get the treatment they need. In what he terms “one of the largest and most pervasive racial disparities,” Harold W. Neighbors notes that African Americans are far less likely than white Americans to get outpatient care for depression—“regardless of income, education, or insurance coverage.” Neighbors, a professor of health behavior and health education and director of the UM Center for Research on Ethnicity, Culture and Health, is trying to find out why.

One reason may be that African-American communities attach a greater stigma to mental illness, he says. Another may be that they are more mistrustful of professional care. A third possibility is that black families prefer to cope with these problems themselves rather than refer them to health care professionals. Earlier this year, Neighbors’s colleague Linda Chatters, professor of health behavior and health education, published a study showing that social and familial support curbs depressive symptoms in African Americans.

Neighbors is also examining racial disparities in the diagnosis of depression. He’s found that once patients are in the care of clinicians, African Americans are less likely than whites to be diagnosed with depression—and more apt to receive a diagnosis of psychosis or schizophrenia. The reasons for this are still unclear but seem to be due to subtle differences in the ways that blacks and whites talk to clinicians about depression.

Like Eisenberg, Neighbors hopes his work will eventually lead to new interventions. “We need more mental health education that focuses on both consumers, particularly men, and professionals,” he says.

Depression, of course, is just one aspect of mental health, which is itself a burgeoning area for public health research and teaching. In 1999, the U.S. Surgeon General issued a report recognizing the “inextricably intertwined relationship between our mental health and our physical health and well-being.”

At SPH, both Neighbors and Eisenberg offer courses on mental health, and other faculty members are conducting studies on a range of mental health issues, from Alzheimer’s disease to Post-Traumatic Stress Disorder, substance abuse, and schizophrenia.

Former SPH Dean Noreen Clark says it’s high time to end the “unnatural schism” between mental and physical health. Through the school’s Center for Research on Managing Chronic Disease, which she directs, Clark is investigating the interaction of mental and physical health. The self-regulation model she and her team have developed—and that’s been used by the Depression Center for some of its work—provides a good basis for understanding how depression and chronic diseases are linked. “The relationship between depression and illnesses such as asthma, diabetes, and heart disease is not well understood,” Clark says, “but there is no question that the presence of depression makes the management of any disease more problematic.”Greden believes that if depression can lose the last vestiges of its stigma and be viewed as just another disease—as cancer, which once had a considerable stigma, now is—then other mental health issues, many of which are still viewed with suspicion, will follow. “We will get spinoff,” he insists. “I actually see it as a domino effect, cascading.”

Galea, who describes his research, broadly speaking, as “the epidemiology of mental health,” argues that depression is “fundamental to public health” because it is a “fundamental determinant of well-being and also a determinant of health in other dimensions.”

Grazier thinks it critical that scientists, policymakers, advocates, and clinicians do their utmost to enable “healthy, fulfilling lives for those stricken with depression.” She speaks for many when she adds, “I really think this disease gets at the soul of public health.”

Article written by Leslie Stainton; image "Naked Young Man Sitting by the Sea," Hippolyte Flandrin, 1836, The Bridgeman Art Library/Getty Images.

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