By Emma Young

After a traumatic event, some people develop post-traumatic stress disorder (PTSD) – generally within about a month – while others don’t. Identifying those most at risk could allow for targeted interventions, aimed at stopping the disorder developing. So how do you spot these people?

One way of exploring this question involves viewing PTSD as a dynamic process in which symptoms interact over time to cause the disorder, and some symptoms likely play a bigger causal role than others. So if you can identify the most problematic symptoms, and the people displaying them, at an early stage, then you can work out not only who to target but which symptoms to focus on.

In a new paper due for publication in Psychological Medicine and released as a pre-print at the Open Science Framework, a team of researchers from Israel and Amsterdam conducted just such an analysis on data collected from Israeli civilians during the 50-day Israeli-Gaza war of 2014. “It is important to note that collecting [this kind of] data regarding traumatic stress symptoms during a conflict situation is unparalleled in the literature,” the researchers write.

Talya Greene at the University of Haifa led the study of 96 people who were living in communities that were exposed to rocket fire. The participants were recruited via adverts and entered the study between eight and 24 days into the conflict. Twice a day, for 30 days, they received a personalised email link to an online version of a 20-item diagnostic checklist for PTSD.

This checklist asks people to self-report on four categories of symptoms: intrusions (such as nightmares and flashbacks); avoidance (of thoughts about and reminders of the traumatic event); negative alterations in mood and thoughts (such as amnesia, blame of self and others, and reduced emotion); and alterations in arousal and reactivity (which measures, among other things, irritability and anger, sleep problems, hyper-vigilance, difficulties in concentrating, and the startle response – an involuntary reaction to a flash of light, a loud noise, or a sudden, potentially threatening movement).

Every morning, and every evening, the participants recorded any symptoms that they had experienced since completing the previous checklist.

The researchers found that showing the startle response was clearly the most important predictor of future PTSD symptoms. Reduced emotion, blame, negative emotions and an avoidance of thoughts relating to the conflict were also, in order of decreasing importance, predictive of future symptoms. Participants who showed any of these five symptoms earlier in the study (but the startle response, especially) were more likely to show even more PTSD-related symptoms later on – and those who had more of these predictive symptoms early on developed even more of the other symptoms of PTSD over time.

The researchers believe this means these are the specific symptoms that could indicate PTSD vulnerability and that targeting them early on could have a preventative benefit.

There were some limitations to the study. One is that it began during the conflict period, and in fact for many participants the conflict was still unfolding by the time they completed their final checklist. PTSD usually develops in the month after a trauma, but in some cases, it takes much longer to appear. These findings may not apply, then, after a trauma. Also, as the researchers themselves point out, they didn’t take some potentially relevant variables – such as gender, trauma history and severity of exposure to the conflict – into account in their analysis. And it would have been interesting to know which – if any – of the participants would have met the criteria for a diagnosis of PTSD (a process that requires more than completion of a symptom checklist.)

Still, as the researchers conclude: “More studies in this vein can elucidate the complex processes by which PTSD symptoms crystallise into disorder and indicate possible causal mechanisms that drive the development of PTSD. This in turn could have clinical implications for identifying the relevant importance of symptoms as targets for interventions.”

—Dynamic networks of PTSD symptoms during conflict

Image: A wounded Israeli soldier arrives at a hospital for treatment on July 20, 2014 in Ashkelon, Israel. (Photo by Andrew Burton/Getty Images)

Emma Young (@EmmaELYoung) is Staff Writer at BPS Research Digest