Nearly two months after the Boston Marathon bombing on April 15, 2013, many who have suffered physical injuries have embarked on the road to recovery. However, the bombing was a traumatic event that affected the entire city, and the long-term psychological impact of the bombing on the city’s inhabitants is only just starting to be understood.

After a traumatic event, many people experience some stress-related reaction, but many recover naturally over time and come away without long-term psychological impacts that disrupt their lives. Those who have previously experienced trauma, whether in war or domestically, are at a higher risk for episodes of posttraumatic stress disorder (PTSD) following exposure to a new trauma. Some people are less susceptible to relapse, and research is still trying to understand why there are individual differences in resilience.

At the time of the Boston Marathon bombing, Cogito was engaged in a clinical trial involving Cogito Companion, a smartphone application that continuously and passively monitors psychological health and well-being using built-in mobile sensors and survey questions. The bombing offers a unique pre-and post-disaster dataset for understanding the longitudinal trajectories and risk factors for PTSD following trauma. Initial analyses of the data show that survey participation dropped by ~50% during the two weeks immediately after the Boston bombing, perhaps an early indication of the PTSD symptom of withdrawal. Of those that did respond, participants reported an average of ~14% increase in severity of attitudes and behaviors linked with depression and PTSD in the two weeks following the bombing than they did in the two weeks prior.

Cogito is continuing to analyze the trial’s rich dataset, which includes data on the physical activity, social interaction, sleeping patterns, and mood of the trial participants before and after the Boston bombing. We are proud to support efforts to better understand the psychological impact of traumatic events, enable earlier detection of distress, and identify the factors that make some people more resilient than others.