These experiences are scary enough to read about and watch, but what are they like to live through? Are hostages irrevocably damaged, or can they recover and return to their normal lives?

Contrary to what one might expect, research indicates that not all survivors of terrorism and hostage crises develop mental-health conditions like anxiety, depression, or post-traumatic stress disorder. Many return to normalcy with time, and some may actually fare worse if they go through immediate mental-health interventions. Still, in the short-term, survivors are likely to experience traumatic flashbacks and seek to avoid triggers.

“Let’s say those people in Paris stop going to the grocery store, because that’s where [the attack] happened, or to Jewish gatherings, because [the attack] targeted Jews, and they don’t want to talk to anybody about it,” said Anne Speckhard, an adjunct associate professor of psychiatry at Georgetown University Medical School. “That’s very likely, and completely normal after a traumatic incident.”

Speckhard, who is the author of Talking to Terrorists and an expert on PTSD, added that it is important to normalize symptoms of trauma for survivors, so that they don’t develop uncontrollable fear, among other problems. But, she admitted, clinicians disagree on what form early intervention should take; for example, some believe it is ineffective or harmful to perform immediate psychological debriefing with victims, because the psychic and physical wounds are still too fresh. Advocating a “middle line,” Speckhard said it’s useful to inform victims of the various ways in which acute stress may manifest itself.

Of course, not all victims of violence respond to and cope with it in the same way. A 2009 review of hostage-taking literature identified three types of psychological harms to survivors: cognitive, emotional, and social. These included impaired memory, intrusive flashbacks, hypervigilance, anxiety, anger, depression, guilt, and withdrawal from others. Certain victims, the review noted, will even deny that the hostage-taking has occurred, as a means of delaying psychic pain and having to radically adjust.

Simon Wessely, a psychologist at King’s College London, said the extent to which people are traumatized by an event results from a mixture of vulnerability factors, like genetics and personality, and the nature of the event itself. For example, civilians involved in a terrorist incident are more likely to develop psychological problems than are certain professionals who may be trained in how to respond.

Perhaps the most widely floated terms regarding hostage mental health, however, are PTSD and Stockholm syndrome. The former describes an anxiety disorder that may arise after a person suffers a harrowing event like sexual assault, military combat, grave injury, or threat of imminent death. According to the American Psychiatric Association’s DSM-5 manual, a diagnosis of PTSD requires a series of criteria to be met, including recurrent intrusion of the traumatic event, avoidance of triggers, negative mood changes, sleep disturbance, and duration of symptoms for more than one month.