The IMPACTS study showed that—six months after the events—psychological trauma remained significant among those exposed (directly or indirectly) to the threat. Furthermore, witnesses who were not directly threatened also exhibited psychological distress. While specialized care was substantial for those most exposed, it appears insufficient for others. Identifying and offering medical and psychological support to all victims—whether they are witnesses or were directly threatened—is a major challenge. Indeed, people who were not directly threatened do not spontaneously think to seek help and/or do not discuss it with their doctor. Some feel guilty toward the injured and bereaved. This guilt can be a barrier to seeking care. Our findings suggest strengthening information and access-to-care systems for people not directly threatened, including in the medium and long term following the events.

Beyond psychological disorders, particularly PTSD, which have been extensively described in other post-attack contexts, the consequences on overall health were significant, both among the general population living near the event and among first responders. One-quarter of individuals reported having consulted a healthcare provider for somatic symptoms (sleep disturbances, fatigue, cardiovascular, musculoskeletal, or dermatological issues) that emerged or worsened following the events. More than 20% reported an increase in their consumption of alcohol, tobacco, and/or cannabis. Hence the importance of raising awareness among healthcare professionals in hospitals and community settings about the issue of psychological trauma to ensure effective follow-up, with a smooth transition of care from the hospital to community-based medicine.

From the perspective of those affected, it was noted that the health impact of exposure to the attacks could take on a more somatic form, such as sleep disorders, fatigue, back pain, etc. For this highly exposed population, widespread training on the psycho-traumatic consequences would help prevent adverse health effects and facilitate access to initial psychological support. Making initial contact with medical and psychological care providers a standard procedure for everyone would prevent any stigmatization. This remains an avenue worth exploring. Similarly, taking into account factors of vulnerability—such as the fatigue of responders deployed across multiple sites or the degree of exposure to the threat—is a point worth emphasizing.

International literature has often focused on those directly involved in the event or on the general population. IMPACTS examined not only victims who were injured or directly threatened, but also emergency medical responders—including volunteer first responders (from nonprofit organizations) and professional first responders (such as firefighters)—law enforcement officers, and witnesses living or working near the sites of the events. The main strength of IMPACTS was active field research. Participants were recruited through inclusion questionnaires mailed to the addresses of people living or working within a 50-meter radius of the event. This made it possible to recruit 102 people living or working near the attacks whose daily lives had been significantly disrupted by the attacks. Our results show that some individuals in this population—rarely surveyed in post-attack studies—may experience a set of symptoms meeting the exposure criteria for post-traumatic stress disorder.
In other words, their risk of developing mental health disorders is higher than that of the general population. The approach of identifying indirectly affected individuals was particularly effective because these people are not usually part of emergency response and care networks, even though they are potentially impacted, as our study demonstrates. The option to respond to the inclusion questionnaire by mail or email allowed us to reach individuals who are less accustomed to using the internet (the elderly, socioeconomically disadvantaged individuals).
Furthermore, unlike the vast majority of studies examining the psychotraumatic impact of terrorist attacks, our survey was not limited to assessing PTSD. We also addressed depression and anxiety disorders, as well as the perceived impact on daily life in terms of physical health or substance use.

Finally, our study was conducted by psychologists trained in psychotrauma. This allowed the interviewees to be referred to care if needed and to receive assistance (psychological, social, legal) tailored to their needs.

These initial findings from the first wave of IMPACTS will be consolidated and expanded upon with the completion of the second interview, conducted between June and October 2016 (12 months after initial enrollment). This longitudinal follow-up was conducted in collaboration with the Social Epidemiology Research Team at the Pierre Louis Institute of Epidemiology and Public Health (Inserm-Sorbonne Universities UPMC) and the University of Paris 13. More than 350 of the 473 people recruited for this second wave agreed to participate. Finally, a final wave is planned three years after the events. This follow-up will allow us to measure the remission, persistence, or reactivation of disorders due to events that have occurred since then. It will also help us understand the consequences of the attacks on their family or professional lives, as well as the care trajectories (interruptions and resumptions of care) undertaken by these individuals.

Building on the experience of the IMPACTS study, Santé Publique France has launched a study with the same objectives, but using a web-based questionnaire targeting individuals directly affected by the November 2015 attacks. This study, ESPA November 13, was designed in collaboration with the University of Paris 13 and implemented in partnership with the “November 13” research program. This work will help validate the findings of IMPACTS to continue supporting public authorities in their efforts to assist populations affected by the attacks.
All of these studies are part of an international collaboration (via a COST—European Cooperation in Science and Technology) initiative: the European Research Network on Terror, led by the Norwegian Centre for Violence and Traumatic Stress Studies, in which Santé publique France is involved alongside other European institutes.