CENTERS FOR DISEASE CONTROL AND PREVENTION
Volume 16 • Number 1 • Winter 2003

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Bridging the Artificial Gap Between Physical and Mental Illness

Physical and mental health are very much intertwined, especially in the case of depression. Physical conditions often result in mental health complications; likewise, depression can manifest itself through physical symptoms. People with depression may adopt unhealthy coping behaviors, such as smoking or overeating, that further contribute to poor physical health. Depression commonly disturbs sleep, appetite, job performance, and the ability to enjoy things previously found pleasurable. 

“Research has revealed that people with depression are high utilizers of medical care,” said CDC’s Daniel P. Chapman, PhD, MSc, a psychiatric epidemiologist. “They often have physical complaints such as fatigue or sleep and appetite disturbances, which may really be manifestations of depression. So early detection and treatment of depression not only prevent needless suffering but are also cost-saving.” 

A 1999 report prepared by the office of the U.S. Surgeon General estimated that at least one in five Americans experiences mental illness, including depression, in any given year. 

“The message I am working hard to get out to all Americans is that we must be as vigilant about our mental and emotional health as we are about our physical health and safety,” said U.S. Surgeon General Richard Carmona in a recent speech to the Mental Health Association of Rhode Island and the Allied Advocacy Group for Collaborative Care. 

Scientists from the Global Burden of Disease and Injury project, a collaborative effort of the Harvard School of Public Health, the World Health Organization, and the World Bank, recently analyzed current health trends in each country and made projections of what the major health problems are likely to be in 2020. According to this project, the number one worldwide health threat by that year will be heart disease, followed closely by depression and other psychiatric illnesses. 

Untreated depression is universally believed to be the leading cause of suicide. Research has demonstrated that depression also is a leading cause of disability—major depression currently is the fourth leading cause of disability in the world and is expected to become the second leading cause by 2020. 

Managing depression can be costly. A 1993 study by Greenberg et al. estimated that $43.7 billion is expended annually for depression-related health care costs in the United States alone. Recent trends suggest that although most people suffering from depression do not receive treatment, those who do are far more likely to receive expensive psychotropic medication and slightly less likely to receive psychotherapy than they were in 1987. 

It is generally held that a combination of psychotherapy (most notably, cognitive behavioral therapy and interpersonal therapy) and medication is the most effective treatment for major depression. Newer antidepressant medications are safe and effective, have fewer side effects than previous ones, and are better tolerated over longer periods of time. Exercise and special diets may also be helpful. 

Depression Is an Ongoing Area of Research 
Research has shown that adverse childhood experiences such as abuse and household dysfunction not only cause unhealthy coping behaviors in young people (for example, smoking, heavy alcohol use, overeating, promiscuity, drug use) but also may lead to the development decades later of injuries and the chronic diseases that are the most common causes of death and disability in this country, including heart disease, cancer, and chronic lung and liver disease. CDC investigations have shown that adverse emotional experiences during childhood also play an important role in the development of depression during adulthood. These findings have important implications for the exploration and creation of preventive interventions. Because depression and anxiety frequently coexist, NCCDPHP is now collaborating with the American Psychiatric Association’s Psychiatric Research Network in examining the unique role of anxiety in the course and treatment of depression. 

In other research, “work we’ve done at NCCDPHP has documented major medical comorbidities associated with hospitalization for depression—primarily circulatory, metabolic, and endocrine disorders,” Dr. Chapman explained. Another NCCDPHP study involving persons whose disability was not attributable to a psychiatric disorder revealed a linear relationship between the degree of disability and the prevalence of depressive disorders: the greater the degree of activity limitation, the higher the likelihood the person was depressed. 

Measuring Healthy Days 
In public health and in medicine, the concept of health-related quality of life (HRQOL) refers to a person’s or group’s perceived physical and mental health over time. For a long time, physicians have informally assessed the HRQOL effects of illness in their patients by simply asking how they have been feeling lately. More recently, as valid measures are developed, HRQOL often has been assessed in clinical research and, increasingly, in patient care as well to help physicians better understand how illness interferes with people’s day-to-day life.

“Mental health is an essential element of health-related quality of life—perhaps the most important element,” said CDC’s David Moriarty, BS, a program analyst who coordinates CDC’s HRQOL assessment program. At the population level, health-related quality of life surveillance may help public health professionals understand how and why depression is linked with chronic disease. According to a May 1998 CDC report, “Perceived mental distress is a key component of HRQOL and is believed to be an important determinant of health behaviors related to chronic disease and disability prevention.” It may be easier to address mental distress than to attempt to change unhealthy behaviors. For example, treatment of anxiety and depression among adults who smoke or are overweight may enable them to make and maintain healthy behavioral changes and reduce their risk of disease and death.

Proportion of healthy, physically unhealthy, and mentally unhealthy days reported by adults at different ages*

*Source: 1993–1997 Behavioral Risk Factor Surveillance System

Four HRQOL measures asking about general self-rated health and recent days of physical health, mental health, and activity limitation have been part of CDC’s core Behavioral Risk Factor Surveillance System (BRFSS) since 1993 and were added, beginning in 2000, to the examination component of its National Health and Nutrition Examination Survey. In 1995 CDC added an optional quality of life module to the BRFSS that includes five more measures of activity limitation and five questions on recent days of pain, depression, anxiety, sleeplessness, and vitality. 

Tracking HRQOL in population surveys with a brief set of Healthy Days measures (see page 3) supports collaborative efforts between the public health and mental health communities in the following ways: 

• Permits the calculation of a Healthy Days summary measure that gives equal weight to mental and physical health perceptions.
• Shows overall disparities and trends for population mental distress. 
• Shows the large perceived health and activity limitation burden of mental disorders. 
• Shows associations between mental distress and behavioral risks. 
• Permits analysis of community indicators of mental distress. 
• Provides a valid and feasible standard for comparing mental distress in community versus research settings. 

CDC’s Morbidity and Mortality Weekly Report (MMWR) has reported findings from BRFSS surveys from 1993 through 1997. Although “healthy days declined only modestly with increasing age, …young adults reported consistently worse mental health versus the oldest age groups, whereas older adults reported considerably more physical health problems than younger adults.”

According to this report, population assessment can be an integral aspect of HRQOL surveillance when it addresses perceived mental distress in general along with symptoms of depression such as anxiety, sleeplessness, and lack of vitality. In the 1995–1997 surveys, the highest levels of recent sleeplessness, the lowest levels of vitality, and the highest levels of recent activity limitation were reported among adults who said that their current activity limitation was primarily caused by depression, anxiety, or some other emotional problem. 

More recently, HRQOL tracking through the BRFSS has revealed a nationwide increase in reported mentally unhealthy days following the September 11, 2001, terrorist attacks in New York City; Washington, D.C.; and Pennsylvania. In a recent MMWR article, CDC reported that three states (Connecticut, New Jersey, and New York) added a terrorism module to their ongoing BRFSS surveys and found suggestions of widespread psychological and emotional effects in all segments of their populations. For example, three-fourths of respondents reported having problems attributed to the attacks, and almost half reported that they experienced anger. Approximately 3% of alcohol drinkers reported consuming more alcohol, 21% of smokers reported an increase in smoking, and 1% of nonsmokers reported that they started to smoke after the attacks. Members of CDC’s Mental Health Work Group and others are studying these findings to better understand the population effects of catastrophic events.

Examples of Putting Healthy Days Measures to Work at the State Level 
In Oregon, findings from the 2000 BRFSS are helping state officials plan programs to improve the health of some population groups. According to an Oregon Health Division newsletter article, “These findings corroborate what we already know about physical health risks . . .. They also shine light on the association between mental health and . . . key behaviors [related to smoking, overweight, and physical inactivity]. In particular, these data suggest that getting Oregonians of all ages to participate in even moderate physical activity might substantially improve both physical and mental health status.” 

Researchers in Michigan used BRFSS findings related to days of poor physical and mental health to examine racial/ethnic disparities. They found that African Americans had more days of poor mental health in the past 30 days (4.3) than whites (3.4), a statistically significant difference. Black men also had poorer physical health and premature mortality from heart disease, cancer, diabetes, and homicide. Said the University of Michigan’s Corinne Miller, DDS, PhD, “How we can best interweave data on mental and physical health needs to be determined.” 

The CDC Mental Health Work Group 
To further explore the link between mental and physical health, CDC created the Mental Health Work Group in 2000. This group includes more than 85 members representing multiple disciplines, divisions, and centers within CDC and its sister agency, the Agency for Toxic Substances and Disease Registry (ATSDR). Its overall goal is to foster collaboration and advancement in the field of mental health in support of CDC’s commitment to promote health, prevent disease and injury, and improve quality of life. 

“We can’t do good public health without addressing mental health,” said the work group’s chairman, Marc Safran, MD, FACPM, PFAPA, a board-certified psychiatrist and medical epidemiologist in CDC’s National Center for HIV, STD, and TB Prevention. Because CDC is not a mental health agency, CDC and ATSDR staff members participating in this work group do so voluntarily out of their firm commitment to advancing the field of public health within the context of CDC’s overall mission.

“The willingness of members to contribute to the Mental Health Work Group in addition to their daily responsibilities has made the group a success,” said Dr. Safran. 

Members of the work group were instrumental in fostering CDC’s sponsorship of a major international mental health conference in December 2000. The Inaugural World Conference: The Promotion of Mental Health and Prevention of Mental and Behavioral Disorders featured a number of presentations by CDC researchers on health-related quality of life and global strategies for mental health promotion. At this meeting, CDC recommended that international public and mental health groups 

• Analyze existing Healthy Days population data. 
• Adapt Healthy Days measures for their countries. 
• Validate the measures for their populations. 
• Include these measures in other surveys and studies. 

The work group’s Web site (www.cdc.gov/mentalhealth), which is regularly updated by work group members and voluntarily maintained by members of NCCDPHP’s information resource management team, offers information about the group itself as well as about related mental health publications and resources. For those who need mental health information that is beyond the scope of CDC’s mission, the Web site also provides links to a number of mental health organizations in each state that can provide clinical referrals or answers to individual treatment questions. 

The work group’s activities clearly support CDC’s belief that health is more than just the absence of disease. As people live longer lives, CDC and its partners will continue working to monitor and improve the physical and mental health-related quality of those extra years of life. 

Suggested Reading 
“Adult Health Problems Linked to Traumatic Childhood Experiences.” CDC press release, May 14, 1998. Available at www.cdc.gov/od/oc/media/pressrel/r980514.htm.

“Researchers Examine Depression Trends,” by Matt Mientka, U.S. Medicine Information Central, May 2002. Available at www.usmedicine.com/article.cfm?articleID=400&issueID=38.*

The Spread of Depression: Public Health Trends, by Barry R. Bloom, International Herald Tribune, December 3, 1999. Available at www.iht.com/IHT/SR/120399/srl20399h.html.*

Self-Reported Frequent Mental Distress Among Adults—United States, 1993–1996. MMWR, Vol. 47, No. 16, May 1998.

Measuring Healthy Days—Population Assessment of Health-Related Quality of Life. CDC; November 2000. 

Psychological and Emotional Effects of the September 11 Attacks on the World Trade Center—Connecticut, New Jersey, and New York, 2001. MMWR. Vol. 51, No. 35, September 2002. 

Happy and Health-Wise: Measuring Health-Related Quality of Life. Center for Disease Prevention & Epidemiology, Oregon Health Division. CD Summary Vol. 50, No. 17, August 14, 2001.

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