Elsevier

The Lancet

Volume 392, Issue 10144, 28 July–3 August 2018, Pages 302-310
The Lancet

Articles
Police killings and their spillover effects on the mental health of black Americans: a population-based, quasi-experimental study

https://doi.org/10.1016/S0140-6736(18)31130-9Get rights and content

Summary

Background

Police kill more than 300 black Americans—at least a quarter of them unarmed—each year in the USA. These events might have spillover effects on the mental health of people not directly affected.

Methods

In this population-based, quasi-experimental study, we combined novel data on police killings with individual-level data from the nationally representative 2013–15 US Behavioral Risk Factor Surveillance System (BRFSS) to estimate the causal impact of police killings of unarmed black Americans on self-reported mental health of other black American adults in the US general population. The primary exposure was the number of police killings of unarmed black Americans occurring in the 3 months prior to the BRFSS interview within the same state. The primary outcome was the number of days in the previous month in which the respondent's mental health was reported as “not good”. We estimated difference-in-differences regression models—adjusting for state-month, month-year, and interview-day fixed effects, as well as age, sex, and educational attainment. We additionally assessed the timing of effects, the specificity of the effects to black Americans, and the robustness of our findings.

Findings

38 993 (weighted sample share 49%) of 103 710 black American respondents were exposed to one or more police killings of unarmed black Americans in their state of residence in the 3 months prior to the survey. Each additional police killing of an unarmed black American was associated with 0·14 additional poor mental health days (95% CI 0·07–0·22; p=0·00047) among black American respondents. The largest effects on mental health occurred in the 1–2 months after exposure, with no significant effects estimated for respondents interviewed before police killings (falsification test). Mental health impacts were not observed among white respondents and resulted only from police killings of unarmed black Americans (not unarmed white Americans or armed black Americans).

Interpretation

Police killings of unarmed black Americans have adverse effects on mental health among black American adults in the general population. Programmes should be implemented to decrease the frequency of police killings and to mitigate adverse mental health effects within communities when such killings do occur.

Funding

Robert Wood Johnson Foundation and National Institutes of Health.

Introduction

Public awareness of police killings of unarmed black Americans has been galvanised by the high-profile deaths of Oscar Grant, Michael Brown, Eric Garner, Walter Scott, Freddie Gray, and Stephon Clark, among others. Black Americans are nearly three times more likely than are white Americans to be killed by police—accounting for more than 40% of victims of all police killings nationwide—and five times more likely than are white Americans to be killed unarmed.1, 2, 3

Beyond the immediate consequences for victims and their families, police killings might also affect the mental health of people not directly connected to the killings or to the people involved. Racism, like trauma, can be experienced vicariously.4, 5 Police killings of unarmed black Americans might compromise mental health among other black Americans through various mechanisms, including heightened perceptions of systemic racism and lack of fairness,6 loss of social status and self-regard,7 increased fear of victimisation and greater mortality expectations,8 increased vigilance,9 diminished trust in social institutions,10 reactions of anger, activation of prior traumas, and communal bereavement.11

A large literature has shown associations between racism and health outcomes,7, 9, 12, 13 emphasising the pathogenic roles of discrimination and differential access to socioeconomic opportunities.14 However, a causal link between racism and health outcomes has been difficult to show. Police killings of unarmed black Americans have been interpreted by many as an expression of “structural racism”,15, 16, 17, 18 defined by Bailey and colleagues as “the ways in which societies foster [racial] discrimination, via mutually reinforcing [inequitable] systems that in turn reinforce discriminatory beliefs, values, and distribution of resources”.14 Police violence disproportionately wielded against black Americans has been linked in part to the ways officers are trained, methods of identifying and engaging suspects, and uneven enforcement and punishment.19, 20, 21 Negative interactions with police have been associated with worse mental health among black men.22 Descriptive studies suggest an elevated prevalence of depression and post-traumatic stress disorder among black Americans living in communities where specific police killings of unarmed black Americans have occurred.23, 24 Anecdotal evidence from traditional and social media suggests adverse mental health impacts in the wake of these events. However, the population-level health impacts of police killings have not been quantified in nationally representative data.

Research in context

Evidence before this study

Mortality related to police use of force is far more prevalent than official statistics suggest, and there have been several recent efforts to quantify and characterise this mortality burden. Black Americans are nearly three times more likely than are white Americans to be killed by police, with the disparity even larger for individuals who are unarmed.

Little is known about the spillover effect of police killings of unarmed black Americans on the mental health of other black Americans in the general population. We searched PubMed for articles published up to Nov 10, 2017, with the search terms “police” AND (“violence” OR “killing” OR “brutality” OR “use of force”) AND (“mental health” OR “psychological” OR “health” OR “depression” OR “anxiety”) AND (“black” OR “African American” OR “black American”). This search returned 104 articles of which three reported on mental health spillover effects of police violence. Yimgang and colleagues found elevated depressive symptoms among black mothers in Baltimore (MD, USA) following Freddie Gray's death while in police custody. Jackson and colleagues reported a strong correlation between anticipation of negative encounters between black youth and police and heightened depressive symptoms in a sample of pregnant black women in Atlanta (GA, USA). Galovski and colleagues identified high rates of depression in the wake of Michael Brown's death in Ferguson (MO, USA). Geller and colleagues found a link between aggressive policing practices such as stop-and-frisk and the mental health of black men. To date, no study has assessed this relationship in a national, population-representative sample.

Added value of this study

Combining recently compiled, validated data on police killings with national, population-representative data from the Behavioral Risk Factor Surveillance System (2013–15), we assessed the spillover effect of police killings of unarmed black Americans on the mental health of other black American adults living in the same state. We found that the number of poor mental health days increased by 0·14 days (95% CI 0·07–0·22) for each police killing in the previous 3 months. We found no effect on the mental health of white respondents and no effects of police killings of unarmed white Americans or armed black Americans. At a population level, police killings of unarmed black Americans might cause 55 million excess poor mental health days per year among black American adults in the USA.

Implications of all the available evidence

Police killings of unarmed black Americans have significant effects on the mental health of other black Americans in the general population. Interventions are needed to reduce the prevalence of these killings and to support the mental health of communities affected when they do occur.

Our study aims to fill this gap. We estimated the impact of police killings of unarmed black Americans on self-reported mental health of black American adults in the US general population. We used newly released data on police killings combined with nationally representative survey data from 2013 to 2015. We employed a quasi-experimental design that leveraged state and temporal variation in police killings of unarmed black Americans to estimate causal effects.

Section snippets

Data sources and measures

We obtained data on respondents from the US Behavioral Risk Factor Surveillance System (BRFSS), a nationally representative, telephone-based, random digit dial survey of non-institutionalised adults aged 18 years and older. We used self-reported race to identify black American respondents. We also extracted information on respondent sex, age, and educational attainment. We used the 2013–15 BRFSS to match available data on the timing of police killings. We note that some respondents in the 2015

Results

Our final sample included 103 710 black Americans interviewed in the 2013–15 BRFSS, whose mean age was 44·9 years (SD 17·3). After accounting for BRFSS sample weights, approximately half of respondents were women, and half had completed university (table 1). Respondents experienced on average 4·1 days of poor mental health in the month prior to interview; only 2348 (2·42%) survey respondents, who were excluded from the final sample, responded “don't know” or did not answer this question. 38 993

Discussion

Police killings of unarmed black Americans were associated with worse mental health among other black Americans in the general US population. These findings were robust to a wide array of specification checks. Our use of a quasi-experimental methodology, coupled with empirical interrogation of potential violations to the unconfoundedness assumption, allows for a causal interpretation of these estimates.29

Our estimates suggest that police killings of unarmed black Americans have a meaningful

References (45)

  • DR Williams et al.

    Racism and mental health: the African-American experience

    Ethn Health

    (2000)
  • TD Warner et al.

    Adolescent survival expectations: variations by race, ethnicity, and nativity

    J Health Soc Behav

    (2015)
  • TT Lewis et al.

    Self-reported experience of discrimination and health: scientific advances, ongoing controversies, and emerging issues

    Annu Rev Clin Psychol

    (2015)
  • M Alsan et al.

    Tuskegee and the health of black men

    Q J Econ

    (2017)
  • R Catalano et al.

    Communal bereavement and the incidence of very low birth weight in Sweden

    J Health Soc Behav

    (2001)
  • Y Paradies et al.

    Racism as a determinant of health: a systematic review and meta-analysis

    PLoS One

    (2015)
  • DR Williams et al.

    Descrimination and racial disparities in health: evidence and needed research

    J Behav Med

    (2009)
  • K-Y Taylor

    From #BlackLivesMatter to black liberation

    (2016)
  • N Krieger et al.

    Police killings and police deaths are public health data and can be counted

    PLoS Med

    (2015)
  • S Carmichael et al.

    Black power: the politics of liberation in America

    (1967)
  • E Hehman et al.

    Disproportionate use of lethal force in policing is associated with regional racial biases of residents

    Soc Psych Pers Sci

    (2017)
  • M Alexander

    The new Jim Crow

    (2012)
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