The mental health of black American adults is significantly impacted by the police killings of unarmed black citizens, according to a new population-based study published in the journal The Lancet.

With the recent police killings of unarmed black Americans widely perceived to be a reflection of structural racism, the findings highlight the role of this type of racism as a driver of population health disparities, and support recent calls to treat police killings as a public health issue.

The research was led by a team at the Perelman School of Medicine at the University of Pennsylvania and Boston University School of Public Health in collaboration with Harvard University.

According to statistics, police kill more than 300 black Americans — at least a quarter of them unarmed — each year in the United States. Black Americans are almost three times more likely than white Americans to be killed by police and nearly five times more likely to be killed by police while unarmed.

Beyond the immediate consequences for victims and their families, the population-level impact so far has been unclear.

“Our study demonstrates for the first time that police killings of unarmed black Americans can have corrosive effects on mental health in the black American community,” said co-lead author Dr. Atheendar S. Venkataramani, a health economist and general internist at the University of Pennsylvania.

“While the field has known for quite some time that personal experiences of racism can impact health, establishing a link between structural racism — and events that lead to vicarious experiences of racism — and health has proved to be more difficult.”

The study combined data from the 2013-2015 US Behavioral Risk Factor Surveillance System (BRFSS), a nationally representative, telephone-based survey of adults, with data on police killings from the Mapping Police Violence (MPV) database.

The researchers estimated the “spillover” effect of police killings of unarmed black Americans on the mental health of other black Americans living in the general population.

During the three-year study period, 103,710 black Americans participated in the BRFSS survey and rated how many days in the past 30 days they felt their mental health (in terms of stress, depression and problems with emotion) was “not good.”

Half of the participants were women, and half had been to university. A total of 38,993 respondents (49 percent of the sample) resided in a state where at least one police killing of an unarmed black American had occurred in the 90 days just before the survey.

Each additional police killing of an unarmed black American in the 90 days prior to the survey was linked to an estimated 0.14 additional days of poor mental health among black Americans who lived in the same state. The greatest effects were seen 30 to 60 days after the police killing.

Black Americans are exposed to an average of four police killings in their state each year. Applying their findings to the total population of 33 million black American adults, the researchers estimate that police killings of unarmed black Americans could contribute 55 million excess poor mental health days per year among black American adults in the U.S.

These findings suggest that the population mental health burden due to police killings is nearly as large as the population mental health burden associated with diabetes among black Americans.

The negative effects on mental health were limited to black Americans, and exposure to police killings of unarmed black Americans was not tied to any changes in self-reported mental health of white Americans. Exposure to police killings of armed black Americans was also not associated with changes in self-reported mental health among black or white Americans.

“The specificity of our findings is striking,” said co-lead author Dr. Jacob Bor, a population health scientist at the Boston University School of Public Health. “Any occasion in which police resort to deadly force is a tragedy, but when police use deadly force against an unarmed black American, the tragedy carries with it the weight of historical injustices and current disparities in the use of state violence against black Americans.”

“Many have interpreted these events as a signal that our society does not value black and white lives equally. Our findings show these events also harm the mental health of black Americans.”

The researchers suggest that the mental health effects of police killings of unarmed black Americans might be reflected in many ways, including heightened perceptions of threat and vulnerability, lack of fairness, lower social status, lower beliefs about one’s own worth, activation of prior traumas and identification with the deceased.

The researchers note several limitations that warrant further research on the topic.

First, the BRFSS public-use data was limited to state-level identifiers, and there was no information on the extent to which the participants were directly aware of police killings nor whether they were aware of police killings in other states. If police killings affected the mental health of black Americans living in other states, then the findings would be an underestimation of the true impact.

Secondly, the measures used in the BRFSS are self-reported. Thirdly, the research did not focus on other ways in which the criminal justice system disproportionately targets black Americans, and it is likely that other forms of structural racism — such as segregation, mass incarceration, and serial forced displacement — also influence the black population’s mental health.

Finally, the study did not include data on other vulnerable populations, such as Hispanics or Native Americans, nor did it consider the impact of police killings on the mental health of police officers themselves.

Source: The Lancet