Author Ivy Tso said:
"Other studies have shown that the 9/11 attacks resulted in a wave of stress and anxiety across the United States. 8-10 percent of the residents of New York City reported symptoms consistent with post-traumatic stress disorder (PTSD) and depression while 40 percent of Americans across the country experienced significant symptoms of stress related to the attacks."
Tso and team carried out a study within a week of the 9/11 attacks and assessed 31 students in Boston, Massachusetts. None of them had been directly connected to the New York attacks - they represented members of the general public in America.
They were shown 90 pictures:
- 30 contained images of the 9/11 attacks
- Some were negative but not related
- The rest were neutral and not related
"The results of our study indicate that participants' brainwave responses during processing of the images deviated from normal in proportion to their self-report distress level directly related to the 9/11 attacks."
They found that the stress-related neural deviations were similar to the characteristics observed in people suffering from post-traumatic stress disorder (PTSD), such as suppressing unwanted thoughts, hypervigilance, and diminished attention.
"This finding is significant as our participants were young, unmediated, highly functional individuals and while their distress was clearly below clinical threshold, their brain responses to emotional information were affected the same way, though not to the same degree, as in PTSD. This makes us rethink whether distress reactions should be considered a spectrum of severity, rather than simply divided into normal vs. clinical categories."