MICHEL MARTIN, HOST:

Now we're going to talk about a subject that has become one of this country's flashpoints - police shootings of unarmed black men. It happened again last Tuesday in Pittsburgh, where Antwon Rose Jr. was shot three times as he ran away from police during a traffic stop. A neighbor caught it all on camera. The video was widely shared and inspired three straight days of protests in Pittsburgh.

But the negative effects of that shooting won't end whenever the demonstrations stop or the reporting ends - this according to a study published in The Lancet medical journal. That study looked specifically at states that had a police killing of an unarmed black man in the three months leading up to the survey. And it found that these violent encounters have a direct effect on the mental health of black Americans living in communities that have experienced police violence. The telephone survey asked respondents how many days their mental health was not good. Black respondents in states with recent police shootings were found to have significantly more of those not good days.

Dr. Atheendar Venkataramani is one of the study's authors. He's an assistant professor in medical ethics and health policy at the University of Pennsylvania's Perelman School of Medicine. He joined me from member station WBUR in Boston, and I started our conversation by asking him why he and his fellow researchers wanted to look into the link between police killings and mental health.

ATHEENDAR VENKATARAMANI: My co-authors and I were very struck by the images of police killings of unarmed black Americans, and we had seen in some small, local studies, as well as through our social networks and on social media, the kinds of things that black Americans who weren't directly part of the event but had heard about it or read about it or seen it through the videos that were released - the kinds of things they were saying about how they felt - what it made them feel and what their mental state was after viewing or hearing about such an event. And for us, it made us wonder do events like this cross the line from just being upsetting to being something that make us sick? And that's what really motivated our study.

MARTIN: The facts are that black Americans, as you point out in the study, are nearly three times more likely than white Americans to be killed by police. They are five times more likely than are white Americans to be killed unarmed. I just think that's important to point out because it's important to note that white Americans are also killed by the police, but it is far more likely that an African-American male particularly will be unarmed when that occurs.

So part of the reason that I raised that is to ask whether you saw any similar effects of other groups? Like, did, for example, killings of white Americans stimulate a similar effect? Do we have any comparison that we can draw upon?

VENKATARAMANI: Absolutely. So we looked at the police killings of armed black Americans and the police killings of unarmed white Americans, which don't necessarily have that same kind of salience to people as far as their relationship to structural racism. And when we looked at the impacts of those kinds of events, we didn't find any impact on mental health nor did we find any impact on mental health of white Americans who were exposed to police killings of unarmed black Americans.

MARTIN: And you know, the survey focused on people and communities where these shootings occurred. But we live in a time when many of these deaths were caught on camera. They've been widely shared. Do you feel comfortable extrapolating that this effect may be broader than the people who actually lived in the places where these incidents occurred?

VENKATARAMANI: Yeah, I think we do. And so for example, Eric Garner's killing was seen by everybody in the country. And for the purposes of our statistical design, we considered people in New York State exposed. So one of the things we think is striking is that we find these large population-level effects even when we know that we are likely to be underestimating the true burden.

MARTIN: The summary says that, you know, the interpretation is that, you know, police killings of unarmed black Americans have adverse effects on mental health among black American adults and the general population. And it suggests that programs should be implemented to decrease the frequency of police killings and to mitigate adverse mental health effects.

What would that look like? I mean, what do you hope people will do as a result of this study which validates what, frankly, has been sort of widely discussed informally among many people for some time?

VENKATARAMANI: We don't believe we're telling people in the black American communities something that they don't know. I think what this study does is provides a public health rationale to further try to understand why police killings occur of unarmed black Americans. And it further motivates policies and programs that would try to reduce those events.

And from the clinical side, as a physician, these events really kind of show you that when something happens in a community that there is a trauma that is a pathology, meaning it's a true illness, and that health systems - community health centers, public health organizations - can try to rally around people to make sure that people are OK and that we're treating the burden of disease that's there.

So I think that's why it's useful to put numbers around something that many people have noted anecdotally because it sharpens the case for action, and it also lets us know the scope of the problem and potentially how we would need to address it.

MARTIN: That's Dr. Atheendar Venkataramani. He's one of the authors of a study published in The Lancet which looked at the mental health effects of police shootings on black Americans.

Thanks so much for speaking with us.

VENKATARAMANI: Thank you.

MARTIN: I also want to mention that the study was funded by the National Institutes of Health and the Robert Wood Johnson Foundation. The latter is also a supporter of NPR. Transcript provided by NPR, Copyright NPR.