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.