Over a decade ago, I wrote a piece for a psychiatric journal entitled “Is Bigotry a Mental Illness?” At the time, some psychiatrists were advocating making “pathological bigotry” or pathological bias—essentially, bias so extreme it interferes with daily function and reaches near-delusional proportions—an official psychiatric diagnosis. For a variety of medical and scientific reasons, I wound up opposing that position.

In brief, my reasoning was this. Some bigots suffer from mental illness, and some persons with mental illness exhibit bigotry—but that doesn’t mean that bigotry per se is an illness.

Yet in the past few weeks, in light of the hatred and bigotry the nation has witnessed, I have been reconsidering the matter. I’m still not convinced that bigotry is a discrete illness or disease, at least in the medical sense. But I do think there are good reasons to treat bigotry as a public health problem. This means that some of the approaches we take toward controlling the spread of disease may be applicable to pathological bigotry, for example by promoting self-awareness of bigotry and its adverse health consequences.

In a recent piece in the New York Times, health-care writer Kevin Sack referred to the “virulent anti-Semite” who carried out the horrific shootings at the Tree of Life synagogue in Pittsburgh on Oct. 27, 2018.

It’s easy to dismiss the term “virulent” as merely metaphorical, but I think the issue is more complicated than that. In biology, “virulence” refers to the degree of pathology, or damage, caused by an organism. It differs from the term “contagious,” which refers to a disease’s communicability. But what if, in an important sense, bigotry is both virulent and contagious—that is, capable of both causing damage and spreading from person to person? Wouldn’t a public health approach to the problem make sense?

The Harm to Victims and to Haters

There is little question among mental health professionals that bigotry can do considerable harm to the targets of the bigotry. What is more surprising is the evidence showing that those who harbor bigotry are also at risk.

For example, research by psychologist Jordan B. Leitner has found a correlation between explicit racial bias among whites and rates of circulatory disease-related death. Explicit bias refers to consciously held prejudice that is sometimes overtly expressed; implicit bias is subconscious and detected only indirectly.

In effect, Leitner’s data suggest that living in a racially hostile community is related to increased rates of cardiovascular death for both the group targeted by this bias—in this case blacks—as well as the group that harbors the bias.

Writing in the journal Psychological Science, Leitner and his colleagues at the University of California Berkeley found that death rates from circulatory disease are more pronounced in communities where whites harbor more explicit racial bias. Both blacks and whites showed increased death rates, but the relationship was stronger for blacks. Although correlation does not prove causation, clinical psychology professor Vickie M. Mays and colleagues at UCLA have hypothesized that the experience of race-based discrimination may set in motion a chain of physiological events, such as elevated blood pressure and heart rate, that eventually increase the risk of death.

It’s unlikely that the adverse effects of discrimination and bigotry are limited to blacks and whites. For example, community health sciences professor Gilbert Gee and colleagues at UCLA have presented data showing that Asian-Americans who report discrimination are at elevated risk for poorer health, especially for mental health problems.

But Are Hatred and Bigotry Contagious?

As the adverse health effects of bigotry have been increasingly recognized, awareness has grown that hateful behaviors and their harmful effects can spread. For example, public health specialist Izzeldin Abuelaish and family physician Neil Arya, in an article titled “Hatred—A Public Health Issue,” argue that “hatred can be conceptualized as an infectious disease, leading to the spread of violence, fear, and ignorance. Hatred is contagious; it can cross barriers and borders.”

Similarly, communications professor Adam G. Klein has studied the “digital hate culture,” and has concluded that “the speed with which online hate travels is breathtaking.”

As an example, Klein recounted a chain of events in which an anti-Semitic story (“Jews Destroying Their Own Graveyards”) appeared in the Daily Stormer, and was quickly followed by a flurry of anti-Semitic conspiracy theories spread by white supremacist David Duke via his podcast.

Consistent with Klein’s work, the Anti-Defamation League recently released a report titled, “New Hate and Old: The Changing Face of American White Supremacy.” The report found that, “Despite the alt right’s move into the physical world, the internet remains its main propaganda vehicle. However, alt right internet propaganda involves more than just Twitter and websites. In 2018, podcasting plays a particularly outsized role in spreading alt right messages to the world.”

To be sure, tracking the spread of hatred is not like tracking the spread of, say, food-borne illness or the flu virus. After all, there is no laboratory test for the presence of hatred or bigotry.

Nevertheless, as a psychiatrist, I find the “hatred contagion hypothesis” entirely plausible. In my field, we see a similar phenomenon in so-called “copycat suicides,” whereby a highly publicized (and often glamorized) suicide appears to incite other vulnerable people to imitate the act.

A Public Health Approach

If hatred and bigotry are indeed both harmful and contagious, how might a public health approach deal with this problem? Abuelaish and Arya suggest several “primary prevention” strategies, including promoting understanding of the adverse health consequences of hatred; developing emotional self-awareness and conflict resolution skills; creating “immunity” against provocative hate speech; and fostering an understanding of mutual respect and human rights.

In principle, these educational efforts could be incorporated into the curricula of elementary and middle schools. Indeed, the Anti-Defamation League already offers K-12 students in-person training and online resources to combat hatred, bullying, and bigotry. In addition, the Anti-Defamation League report urges an action plan that includes enacting comprehensive hate crime laws in every state, improving the federal response to hate crimes, expanding training for university administrators, faculty and staff, and promoting community resilience programming, aimed at understanding and countering extremist hate.

Bigotry may not be a “disease” in the strict medical sense of that term, akin to conditions like AIDS, coronary artery disease, or polio. Yet, like alcoholism and substance use disorders, bigotry lends itself to a “disease model.” Indeed, to call bigotry a kind of disease is to invoke more than a metaphor. It is to assert that bigotry and other forms of hatred are correlated with adverse health consequences, and that hatred and bigotry can spread rapidly via social media, podcasts, and similar modes of dissemination.

A public health approach to problems such as smoking has shown demonstrable success; for example, anti-tobacco mass media campaigns were partly responsible for changing the American public’s mind about cigarette smoking. Similarly, a public health approach to bigotry, such as the measures recommended by Abuelaish and Arya, will not eliminate hatred, but may at least mitigate the damage hatred can inflict upon society.

Ronald W. Pies is a clinical professor of psychiatry at the Tufts School of Medicine.