Over the year-long discussion of health disparities in the MacLean Center for Clinical Medical Ethics seminar series, the health gaps presented between American whites and blacks have been predominantly a one-way street. On nearly every health measure – from infant mortality to diabetes to cardiovascular disease – higher rates are observed for African-Americans. But there’s one health gap where the racial positions are surprisingly flipped, said James Jackson of the University of Michigan in his visit to the series in early May. Over the course of a provocative talk, Jackson demonstrated how this strange reverse disparity in mental health could be hiding a model explaining the physical health gaps that continue to resist reduction efforts.
In a 2007 study, a survey project led by Jackson measured the lifetime prevalence of major depressive disorder in African-Americans, Caribbean blacks, and white Americans. An almost complete reversal from the normal health disparity was observed, with roughly 18% of whites diagnosed with major depression at some point in their lives, compared to only 10.4% of African-Americans. The data, though replicated several times, was initially greeted with skepticism by observers who were mostly familiar with biased data based on hospital admissions, Jackson said.
“When people noticed this, they really began to contort the data,” said Jackson, a psychologist and director of the Institute for Social Research at the U. of M. “The argument was that there must be something wrong with the way it was assessed, because everybody knows that African-Americans have to have higher rates of psychiatric disorders than whites.”
But now that the reverse disparity has been verified in many different populations, Jackson has started to ask why these differences exist. His working theory hinges on two other observations: the delayed appearance of physical health disparities over the course of life, and cultural differences in the way people cope with stress. When well-known health disparities on measures such as diabetes or hypertension are broken down by age, there is not a consistent gap between blacks and whites, but a gap that emerges and rapidly grows in middle age (45-64 years old). Putting aside differences in infant mortality rates, some evidence actually suggests that black children are healthier than white children on many measures, Jackson said.
The growing gap in health measures over the life course is paralleled by another growing gap – in the frequency of poor health behaviors. In white populations, smoking rates peak in young adulthood and then decline, while the rate in black populations accelerates with age. The same pattern holds true for heavy alcohol use and drug use, Jackson said, while frequency of vigorous physical activity declines with age faster for black females than white females. Obesity is more complex – it is the only black-white difference observed early in life, at least for females – but this gap also widens over life course, regardless of socioeconomic status.
The core of Jackson’s theory was to cast those physically unhealthy behaviors not as mere vices, but as methods people use to self-medicate themselves against the stress of daily living.
“If you’re having a bad day…you know it. At the end of the day, your stomach is upset, you have a headache. There are palpable things that are present with regard to the stress reaction to the circumstances,” Jackson said. “But if you are growing a tumor for cancer, you don’t know it, until it reaches a certain stage.”
“If you know you’re having these stress-related kinds of problems, this awareness motivates you to action – you are motivated to do something about the physiological and psychological consequences of stressors in your life. And what do you want to do? People eat comfort food to reduce stress, the activity in the chronic stress response network,” Jackson said. “If I’m stressed, a Twinkie makes me feel better.”
Self-regulating stress can also go beyond junk food, Jackson said, to severe drug and alcohol use. All of these coping strategies may help dampen the stress response and protect mental health, but only at the cost of exacerbating physical health problems.
Jackson’s group found that African-Americans who engage in fewer unhealthy coping strategies (smoking, drinking, or drugs) actually have higher rates of depression, while those who do use eating or drug use to cope with these behaviors have the lower rates reflected in the broader black population. It’s a perverse trade-off, he said.
“Blacks and other groups in society may ‘buy’ their reduced rates of psychiatric disorders, with higher rates of physical morbidities and early mortality,” Jackson said.
This idea might lead some to wonder whether disparities could thus be explained by biological differences in the stress pathway of blacks and whites. But Jackson disagrees with the idea of race as a variable that influences stress response, instead arguing that a stressful life “racializes” individuals in a society where disadvantage is so closely linked to race. In one experiment, Jackson tried to make “white people black” by looking at whites who encountered similar stress variables (i.e. poverty and living conditions) over their life as the average black person in America. Here he found the same trade-off between coping behaviors and mental health: the more unhealthy coping behaviors used, the lower the risk of depression. So the stress produced by a lifetime of hardship and discrimination, not biological factors of race, may be the smoking gun of disparities.
“What you are as a black person at 2 years old is not what you are as a black person at 45 years old,” Jackson said. “Your experiences in society as a black person – or as a white person – are predicated upon the things that happen to you as you move through life.”
[Each academic year, the MacLean Center for Clinical Medical Ethics organizes a series of lunchtime seminars by physicians, biologists, economists, social scientists and other experts covering the biggest questions in health care and ethics. This year’s theme is “Health Disparities: Local, National, Global,” and the series was put together with the Urban Health Initiative, the Global Health Initiative, and Finding Answers. ScienceLife will carry regular coverage of this unique series, and video of the lectures will be posted when available.]