Sri Lanka's Tragedy and the Global Health Burden of Trauma

How traumatic events can shape health

Posted Apr 22, 2019

Co-written with Gregory Cohen, MPhil, MSW, and Shui Yu, MA

Yesterday, a series of bombings in Sri Lanka killed over 200 people and injured hundreds more, in what police have called coordinated terrorist attacks. While the attacks may be over, their health consequences have only begun. In addition to physical injuries, the survivors of the bombings will be at risk of a range of mental health challenges, from depression to post-traumatic stress disorder (PTSD). They are, sadly, not alone in experiencing this risk. The drivers of trauma are all around us—from natural disasters, to gun violence, to racism, homophobia, and the many forms of interpersonal abuse. The bombings are just the latest reminder that trauma is a ubiquitous human experience that touches millions daily and should be of concern to public health.

The Burden of Traumatic Events

Traumatic events are a common experience. A general population survey conducted in 24 countries showed that more than 70 percent of respondents experienced a traumatic event, and 30.5 percent had experienced four or more events. Traumatic events (TEs) range from threatened death, serious injury, or sexual violence, to the unexpected death of loved ones. The most common TE exposures include the unexpected death of a loved one, mugging, experiencing a life-threatening vehicle accident, or experiencing a life-threatening illness or injury.

The Mental Health Consequences of Traumatic Events

Responses to TEs may vary individually and include a range of health consequences, from chronic inflammation to PTSD.PTSD is the sentinel psychiatric disorder associated with traumatic events. PTSD symptoms include intrusive re-experiencing symptoms, avoidance of stimuli associated with the TE, arousal, and reactivity, and disturbances in mood and cognition. In the US, the lifetime prevalence of PTSD is approximately 8 percent, with prevalence being much higher in low-income, African American neighborhoods of Detroit, Atlanta, Chicago, and Philadelphia, where violent crime rates are high. PTSD is linked to a broad range of negative consequences, including increased morbidity and mortality rates and higher risk for suicidal behavior. By way of example, one study showed that the mortality rate among Vietnam veterans with PTSD was 71 percent higher than veterans without PTSD. Such increased mortality was primarily explained by suicide and motor vehicle accidents. A study showed that soldiers who suffered from PTSD were 5.4 times likelier to experience suicidal ideation. In addition to this, the likelihood of suicidal ideation was 7.5 times higher among soldiers with at least two comorbid conditions than among those with PTSD only. Although only a minority of those exposed to TEs develop PTSD, many who do not meet full criteria may nonetheless be classified as experiencing sub-threshold PTSD, with symptoms that are often clinically significant but treatable. There is a broad range of psychological consequences of TEs, including depression.

It is worth noting that diagnosable mental illness is only the “tip of the iceberg” in terms of the behavioral consequences of TEs. Common physical and behavioral responses—including nausea; dizziness; changes in sleep and appetite; withdrawal from daily activities; and feelings of fear, grief, and depression—are much more frequently experienced. Although such responses can last for weeks or months, most people report feeling better within three months after a TE. It is only a minority of persons who proceed to, or continue to experience, diagnosable pathology.

TEs and their consequences are not confined to soldiers, or to persons who we may typically think of as being “in harm’s way.” I illustrate this by drawing on two studies in which I have long been involved. The Detroit Neighborhood Health Study examined the lifetime experience of TEs and PTSD among predominantly African American residents of Detroit. Results showed that the lifetime prevalence of exposure to at least one TE was 87.2 percent, with the unexpected death of a loved one being the most prevalent single exposure, at 70.6 percent. The lifetime prevalence of PTSD in this sample is 17.1 percent and is most common among people who experienced assaultive violence, especially among those who have been raped (32.8 percent) or been badly beaten (31.2 percent). Strikingly, in a sample of Ohio Army National Guard soldiers, 77.6 percent experienced at least one TE in their most recent deployment, while the prevalence of deployment-related PTSD was only 9.6 percent—about half that estimated in the Detroit Neighborhood Study.

How Our Social, Economic, and Cultural Context Modifies the Effect of Traumatic Events

The ubiquity and breadth of the health consequences of TEs readily argue for their importance to the health of populations. Equally salient, however, is the interplay between TEs and the social, economic, and cultural context that shapes population health. For example, supportive networks and social support at the neighborhood level have demonstrated salutary effects on mental health. Collective efficacy, which is defined as “social cohesion among neighbors” and their willingness to intervene for common goods, has been found to help reduce physiological distress and the risk of mental health disorders among residents who experienced loss of resources caused by natural disasters. Collective efficacy can function as a coping resource or mechanism and can have a positive impact on mental health through its link with other neighborhood indicators like poverty or crime. For example, a study of those exposed to the Florida 2004 hurricanes found that collective efficacy was linked with a decreased likelihood of PTSD and depression symptoms. A study of people exposed to Hurricane Sandy showed that higher levels of perceived neighborhood social cohesion, which is a component of collective efficacy, are strongly linked with decreased levels of PTSD symptoms. Examining interactions between individual and community-level factors after Hurricane Sandy, our group found that people with more disaster-related stressors (e.g. displacement, property damage) and who lived in communities with more damage tended to have higher individual service need.

I have often felt that TEs represent a little-discussed, dramatically important determinant of the health of populations. Events like the Sri Lanka bombings appropriately galvanize our attention, calling out the foundational drivers that shape a troubled world. They also need to remind us both of the long-tail mental health consequences of these events, and the need for help for the survivors and their community, and that TEs are remarkably common and have important health consequences for billions worldwide.